Rose kept her steps even as she moved down the hall, walking away from the Doctor and his new companion.
"See yah on the other side," she'd said, as though letting him out of her sight was easy.
"No disappearing without me! I haven't even said hello to the Tardis yet," she'd added, hoping against hope that she didn't sound as desperate and clingy as she felt.
The hug they'd shared in the lab, so familiar her heart ached, had made it almost impossible for her to keep her composure, but she'd turned and left the lab they'd commandeered with her head high.
She'd forced her steps to stay measured, and confident, and she hadn't looked back, unsure in her ability to watch the Doctor take hold of Martha's hand and run.
Unsure if she'd be able to contain her slightly possessive glee if he didn't.
Stepping back into the main hall, she pressed the door closed quickly, and let herself take a steadying breath, eyes scanning the room.
She couldn't see Lazarus, so cut a path across the room towards passing a waiter instead, filling her hand with a fresh glass of champagne that she could pretend to sip as she prowled the perimeter.
She itched to follow the Doctor. To stick to his side and not let him out of her sight, but her years at Torchwood helped her to focus on the current potential disaster. The more ground they could cover, the better, and sticking together in a group wouldn't help them to do that.
"Tish, have you seen Martha and that Doctor anywhere?" A woman asked, her voice sharp and cutting through the buzz of quiet mingling.
The two names drew Rose's attention and she came to a slow stop, raising her drink to her lips and making a show of taking a sip as she listened to the conversation behind her.
"Not since the demonstration," came the answer. Another woman, sounding younger this time.
"Do you know anything about him? Has she ever mentioned him before?"
"Not to me. That blonde woman who was speaking to the Professor seemed to know him though," the second voice said and the hair on Rose's neck stood on end as she felt eyes settle on her. She faked another sip of her drink and scanned the room for Lazarus again.
"The way she followed him..."
The tone was heavy with worry, and Rose smothered a sigh and grimaced. She could almost hear her mother in the sharp mutterings, and only a mother sounded that concerned about a young woman following after a strange man.
"She's a doctor. She's just doing her job!" The younger woman sighed.
"She's not a doctor yet. Never will be, if she doesn't stay focussed—"
"So she's found a bloke. What's the problem— Mum!" The male voice was familiar to Rose, but she didn't have time to wonder where she recognised it from.
A moment later, a heavy hand on her shoulder surprised Rose, and when the grip turned her around, sharply, the glass of champagne slipped from her fingers.
The crystal shattered loudly against the floor, alcohol spilling down the edge of Rose's dress as she took half a step back, the commotion drawing several pairs of eyes and a waiter with cleaning supplies.
Lifting her own eyes from the mess, frowning, Rose studied the older woman standing before her, arms crossed with an expression of stubborn determination etched across her face.
"Can I help you?" Rose asked, letting her gaze flick down to the shattered crystal and back up to the woman she assumed was Martha's mother.
Behind her, Rose could see a young woman looking mortified, and a man she recognised from the parallel world, Leo Jones, who was currently rolling his eyes, hands clasped behind his neck in open frustration.
Rose blinked at the man who had been her research and medical officer as she quickly put together why she'd recognised his voice, before she forced herself to focus on their mother.
The woman didn't seem to realise that her action might have been considered rude, and instead of apologising she took hold of Rose's arm again and tugged her away from the shattered crystal, while introducing herself, and starting what sounded like the beginning of an interrogation.
"My name's Francine Jones," the woman started, her voice still sharp. "That Doctor... Whoever, person. He's wandered off with my daughter and there's just something... off about him."
Francine's fingers twitched against Rose's arm, and the blonde narrowed her eyes slightly and hoped it looked more like confusion than irritation.
"Something's going on," Francine continued. "I can feel it, and I don't trust him. What do you know about him?" The woman all but demanded, and Rose found herself staring at Francine, eyebrows raised in genuine disbelief at her brazenness.
"I know that if he'd knocked my drink outta my hand, he'd have apologised," she couldn't help but snap, and Francine flushed, pulling her hand back from Rose's arm like she'd been stung.
"I'm... I'm sorry. I'm just worried about my daughter, Martha—"
"Look, Mrs Jones," Rose cut her off sharply. She was trying to keep the simmering anger out of her voice, but couldn't stop herself from defending the Doctor against the woman's misguided assumptions.
"I don't know what you're implying, but Doctor Smith is a very old friend of mine. A very good friend of mine, and an all 'round generally good person," Rose said slowly, "so while I appreciate that you are, for whatever reason, concerned about your daughter I would thank you to not cast vague aspersions on the character of one of the greatest people I have ever met," she finished, the words pouring out of her almost without thought.
"But what do you know about him?" Francine pressed, and Rose frowned in response.
"What do you mean?"
"What's his name? His job? Where did he study? Where does he live? Martha's never mentioned this man before, and she's suddenly bringing him to an exclusive event like this..."
Rose crossed her arms and studied Francine carefully. If she'd been anyone but the mother of the Doctor's current companion, Rose wouldn't have hesitated in lying to her.
At the same time, those were a lot of personal questions, that Francine Jones hadn't exactly earned the right to know the answers to and Rose considered how best to respond, walking a thin line between embellished truth and misdirection.
"Doctor John Smith is a genuine genius," she said after a moment. "He's worked for several organizations over the years in a freelance position, but much of his work is classified by one authority or another. I've not seen him in several years, but last I heard he was based up in Cardiff."
Rose tilted her head slightly, and narrowed her eyes in challenge, "Perhaps you should ask your daughter how they met instead of a stranger. Although, considering the third degree I'm receiving, I can understand why she might be reluctant to tell you," she suggested, raising an eyebrow at the woman.
Leo and the other young woman, who Rose assumed was his sister, had been standing nearby as Francine questioned her, but both of them smothering surprising laughs and covering their grins with their hands drew Rose's eyes for a moment as their mother spluttered.
"How dare you—!?" She spat out, and Rose's eyes snapped back to her as her patience frayed and she was suddenly furious.
"No, Mrs Jones. How dare you? You accost me in the middle of a scientific demonstration of world changing significance and you demand information on a man I admire and respect, after making veiled remarks about the quality of his character. All because, as far as I can tell, your daughter seems to realise that she has a right to her own privacy," Rose snapped, struggling to keep her voice soft and low.
"Frankly, I think I've told you more about him than you deserve to know considering your unusual level of hostility towards a man that you have, yourself, admitted to not knowing much about."
Francine's jaw had fallen open in shock, but Rose had made a concerted effort to remain polite and Leo quickly stepped forward while his mother was still standing there in stunned silence and grasped at her arm, tugging her away from Rose.
She could hear the young man telling his mother to let it go while shooting her an apologetic smile over his shoulder that Rose couldn't stop herself from returning, a nod of forgiveness escaping her before she took a deep breath and glanced around the room once more.
While she'd been verbally sparring with Martha's mother, the Professor had re-entered the room and was now moving around the edges, almost circling the room. His movements reminded her of a predator on the hunt, and the disturbing thought forced Rose to suppress a shiver.
Another scan of the room told her that the Doctor and Martha were nowhere to be seen and she started moving towards a table laden with glasses of champagne, that would put her directly in Lazarus' line of sight.
Just as her fingers wrapped around the stem of a fresh glass she heard Lazarus' voice behind her and smothered a shiver of revulsion at having him standing so close.
"Ah, Mal Lupin. I'd recognise that golden hair anywhere," he all but purred, his hand resting lightly against her bare shoulder, and Rose forced out a laugh, a smile settling over her features before she turned to face him, his hand slipping to her waist as she did.
"There's more than one blonde in the room, Professor," she teased, but he simply smiled at her. Rose blinked in surprise when he casually collected her free hand and tucked it around his arm, before beginning to guide her slowly through the crowds and towards the lifts that led to the upper floors of the building.
"But none quite so fascinating as yourself, I'm sure," he offered as they walked.
"Flatterer," she murmured, faking a sip of her new drink and steadying her nerves as they stepped into the lifts.
She knew the Doctor was on the upper floors, and if he was on his way down and found her missing, Rose hoped that he'd take that as a sign that something was wrong. She only had to keep Lazarus distracted.
"The doors to the lift closed and the Professor released her arm, his hand shifting to the small of her back instead, and Rose turned towards him a little in response.
"So, what brought our invitation to your door, Miss Lupin?" He asked, and she tipped her head. Her heart was pounding with adrenaline, and not for the first time she wished she had the same kind of control the Doctor could exhibit over his own physiology.
"How do you mean?" She asked instead.
"Well, everyone who was invited here this evening are either reporters, or scientists. You strike me as neither," Lazarus explained, and Rose lifted an eyebrow.
"I don't know whether to be flattered again, or mildly insulted," she teased, letting her lips lift into a playful smile, despite the cold pit gathering in her stomach, but she forced herself to shrug.
"I'm not a scientist, per se," she agreed, "but I'm an academic of sorts. As you heard earlier, I met Doctor Smith at a discussion in Norway on the theory of interdimensional travel. Sometimes I get asked to liaise with various government departments on their projects and sometimes I get invitations to demonstrations such as this via those same channels."
She elaborated on her fabricated history with ease, grinning up at the scientist as he smirked back at her.
"It seems that I have a rather specific set of skills that are, quite often, in demand," she added, her voice purposefully playful and the Professor laughed.
"Oh, I'm sure."
The lift doors opened and the hand still sitting against the small of her back pressed gently, guiding her out of the lift and onto the top floor of the building.
The offices were dark, shrouded in shadow, but the lights of London were glowing outside the large bank of windows enough that Rose could tell they were alone.
With no sign of the Doctor, Rose swallowed back her nerves and glanced up at Lazarus once more.
"Where are you taking me, Professor?" She asked, disguising her need to know behind a teasing smile, before she gave the room another quick sweep, seeking out any potential escape routes but her options were limited.
Unless she wanted to dive out one of the large windows and fall to the pavement, her only options were the stairs and the lifts and Rose thanked her lucky stars that she'd chosen boots she could run in, instead of the strappy things that Jack had originally suggested.
"Up to the roof," Lazarus answered her inquiry, "I thought you'd like to see the view. The rooftops of London, so to speak."
"Sounds extraordinary," Rose muttered, continuing to let herself be guided through the building and up a final set of narrow stairs, her nerves mounting.
She knew the Doctor was looking for Lazarus, and the weight of the gun strapped to her thigh was reassuring if the Time Lord was late on the scene.
All she had to do was buy the Doctor enough time, she reassured herself as they stepped out onto the roof and she let herself gasp at the truly spectacular view stretched out before her.
If she'd been sharing it with the Doctor, it would have been perfect.
"Oh, wow..." Rose breathed, eyes widening in genuine awe, but as the Professor's arm slid around her waist and he tugged her into his side, she had to concentrate on not letting her body tense and pull away.
Lazarus said nothing, and neither did Rose. She let the moment stay silent and uninterrupted. She could talk to him, and distract him, to buy herself some more time, but if the Professor was willing to stand in quiet contemplation, Rose wasn't willing to waste her limited conversation material until she had no other choice.
All the same, as she stood in the cool London air, she couldn't stop herself from hoping that the Doctor, for once in his life, would arrive just a little early instead of at the very last convenient moment.
After he and Martha had stumbled over the desiccated corpse that had once been Sylvia Shaw, the Doctor had led them back down into the main demonstration hall to look for Ro— Lazarus.
He let his eyes scan over the room, seeking out her familiar form with a single-minded determination, only peripherally aware that Martha was still with him.
"I don't see him," she said softly, "either of them..."
"She can't have gone far. Won't have. Keep looking," the Doctor ordered quietly, his voice tense.
He could see Martha's brother approaching them, but ignored the young man, doing another scan of the room.
"Sorry Martha, mum wants a word with you—"
"Have you seen Professor Lazarus?" Martha asked him, and the Doctor felt a rush of gratitude that the young woman was still focussed.
Of course, a desiccated corpse tended to focus the mind, he admitted to himself hands running through his hair in agitation as he did a third scan of the room, even knowing that if Rose had been there he'd have spotted her familiar form by now.
Martha's hand slapping against his arm snapped his head around just in time to see her brother nodding.
"Yeah. Mum was grilling that blonde friend of Doctor Smith's, and when she made her escape Lazarus pounced," Leo joked, grinning. "She got a thing for genius' or something?" He asked, but faltered beneath the glares he was getting from both the Doctor and Martha.
"Ah, Doctor," Martha's mother called as she approached them, and the Doctor could see Martha wince, but it was her brother who had his full attention and the Doctor stepped closer to Leo.
"Where did they go? Where did he take her?" The Doctor asked, his questions were bordering on a demand, but he didn't have time to soften his tone as Leo blinked at him in surprise.
"Uh... into the lifts," he answered, lifting one hand and indicating a set of doors at the back of the room, "the ones that head upstairs but they're locked to anyone but staff," he offered, and the Doctor could feel his jaw tense.
Out of the way, alone, with a killer.
"Doctor—" Martha's mother tried again, but the Doctor was barely listening enough to hear Martha growl her own irritated response.
"Not now, mum!" She snapped, but the Doctor had already whirled on his heels and started towards the lifts, accidentally knocking Martha's mother's drink, the sparkling liquid splashing across her hand and the floor.
He paused, grasping the glass and making sure it didn't slip from her grip, but the Doctor only paused long enough to make sure that the crystal didn't crash to the ground.
"I'm talking to you!" Francine Jones snapped, and he hesitated just long enough to meet her eyes. If he left it would cause problems, for Martha, for himself, he could feel the tug on the timelines, but if he didn't then Rose...
"Sorry," the Doctor offered, before spinning away from her and running for the lifts, Martha still on his heels.
The sonic in his hand pried the doors open and the pair of them slid inside. Another burst of the sonic, and the lift doors closed again before they'd even fully opened and he sent the lift racing towards the top floor as fast as he dared.
Martha kept shooting him concerned glances, but the Doctor kept his eyes fixed on the rising floor numbers, keeping a tight rein on his building panic.
Rose Tyler had somehow, miraculously, amazingly, come back across the void without shattering the dimensional walls and destroying two universes.
He didn't know how, and part of him didn't particularly care, but there was no way he was going to lose her again now. Not to some mad scientist less than an hour after he'd been able to pull her into a hug once more.
As they approached the top of the building the lift slowed and the doors opened onto the large open office space, with its bank of large windows looking out over London.
Together he and Martha stepped out into the room, and the Doctor spun in a circle, turning his attention back to the sonic in his hand when he saw no sign of Rose.
"Where are they?" Martha asked, but the Doctor was flipping through settings on the sonic, wondering if he could track Rose before he cursed himself softly when he realised it could track Lazarus instead.
"Fluctuating DNA will give off a signature that I might be able to pick up," he muttered, half in answer to Martha's question, and half in explanation.
"If I'm lucky... If I'm very, very lucky..."
'Please, please, please, please, please,' he begged the universe. 'Let me have this one. Give me this one.'
The sonic beeped in his hand and the Doctor's hearts nearly leapt out of his chest as relief flooded him.
"Ah-ha! Got him!" He cried before a frown overtook his face and he glanced between the sonic and the ceiling in confusion.
"Where?" Martha asked
"What?" The Doctor muttered, tapping the screwdriver against his hand before checking the results again. "But... this is the top floor. Where—?"
"The roof!" Martha exclaimed, slapping his arm with the back of her hand, and then they were moving. It only took them moments to find the stairs that led up and the Doctor took them two at a time, Martha still keeping up.
He could hear Lazarus talking, and let himself huff out a soft sigh of relief, slowing as they reached the top of the stairs and signalling for Martha to move quietly as he silently pushed open the door that led to the roof.
"... I've been working towards this for so many years, it's difficult to believe that the moment's finally here," Lazarus was saying, and as the Doctor leant around the brickwork he watched the geneticist lean towards her.
'Too close,' his mind growled but Rose smiled and stepped away from the Professor as though she'd heard his mental snarl, moving to the edge of the roof and leaning back against the stone wall.
He knew the moment she'd spotted Martha and himself lurking in the shadows, because her shoulders relaxed, and her smile softened into something more genuine, but the Doctor didn't let himself relax. She was still too far away, and with Lazarus standing between them.
"Is it how you imagined?" She asked the Professor, her eyes flicking away from the Doctor's as she kept Lazarus distracted with terrifying ease.
"I find that nothing is ever exactly what you expect it to be," the Professor answered her smoothly. "There's always something to surprise you. Between the idea and the reality, between the motion and the act—"
"Falls the shadow," the Doctor completed, stepping out of the shadows and onto the rooftop, hands sliding into his pockets casually as Lazarus spun to face him, his features twisting into something between a sneer and a snarl.
"So, the mysterious Doctor knows his Elliot," Lazarus taunted with a forced smile. "I'm impressed."
"For a Time Lord you have the worst possible timing," Rose grumbled, already taking advantage of the Professor's distraction and putting distance between the man and herself. "Always leaving things to the last bloody second—"
"You sound exactly like your mother," he teased, grinning when she shot him a familiar glare of warning.
Lazarus' attention was turning back to Rose, so the Doctor cleared his throat sharply, and shifted forward another step, keeping the Professor's attention.
"I wouldn't think you had time for poetry, Lazarus," he threw out quickly, "What with being so busy inventing ways to defy the laws of nature, and all."
"You're right, Doctor," Lazarus said, but there was a sneer of distaste on his face now, and the man clasped his hands behind his back, lifting his chin slightly, the superiority rolling off him in waves that the Doctor could almost taste.
"One lifetime will never be long enough to do everything I've dreamed of," Lazarus explained. "Just think how much more I'll accomplish in two, or three, or four," he added with a purr of satisfaction, his smile turning cold and his eyes narrowing as Rose finally made it around the rooftop to stand by the Doctor's side.
"It doesn't work like that," the Doctor said softly, and Lazarus' sharp gaze snapped away from Rose once more, his features settling into a glare.
"Some people live more in twenty years than others do in eighty. It's not the time that matters, it's the person," the Doctor explained, struggling not to turn his eyes on Rose as he spoke. The last thing he wanted was for Lazarus to be any more interested in the blonde than he already seemed to be.
"But if it's the right person? Oh, what a gift it could be!" Lazarus urged, but the Doctor grimaced. He'd lived long enough to know better, and shook his head.
"Or what a curse. Just look at what you've done to yourself," he pushed, sharp eyes catching the slight rippling beneath Lazarus' skin as he lost control of his temper.
"Who are you to judge me?" Lazarus snarled, his body tensing in fury before his face contorted in pain and his back arched dangerously.
Growls of agony began escaping the professor, and he dropped to the floor of the roof, his body contorting to the sound of bones snapping as he shifted.
He morphed into something monstrous. Six limbs, a tail, long neck with Lazarus' face staring back at them. Part man, part scorpion, part mutation, and part something new... or very very old and without a name.
The Doctor felt Rose's hand slide into his, and without looking he let their fingers interlock.
"What the hell's happening to him?" She hissed, but the Doctor shook his head and turned to flee, her hand still clasped in his own, palm to palm.
"Run!" He shouted, urging Martha ahead of him, and his fingers twitched around Rose's hand, making sure nothing could tear them apart again as the three of them flew through the door and back down into the building.
Despite the hug earlier, and despite the danger and running for their lives, it was her hand in his, her skin pressed against his skin, that reassured the Doctor that Rose was truly home.