It isn't the worst thing he's ever done in a lifetime of doing terrible things, but it certainly feels like it.
He doesn't know how long he sits there, slumped against the wall, arms still clasped around the magnaclamp device as a dull nothingness thuds in his ears. It might be hours. It might be days. But it's probably minutes.
Time doesn't make sense at the moment. Unusual for him, to be sure.
At some point he finds himself walking toward the end of the room, slowly, his feet dragging over the floor. He walks to the point where Rose disappeared.
He thinks of energy transference and all of the reassuring quotes that nothing truly ends, and thinks perhaps that the universe can't really be so cruel as this. So maybe, if he tries, he could still sense something of her presence. Or maybe there's one crack left, just one small sliver in the universe where he could pull her through.
The white wall stands in front of him, unconcerned. He presses his ear against it.
There is nothing there, of course. It's just a wall.
Is he sure that Pete's button worked? What if they got pulled into the Void—it all happened so fast?
If he hadn't sent her that first time, would there have been less Void stuff to pull her in, what if what if what if...
He wonders, if they'd taken opposite sides, if he'd have been able to reach the lever without letting go... is there a universe in which that happened?
(He realized early on that sending Rose away in the first place was a mistake; after all, they needed two people to activate the levers, didn't they? He may be a rather magnificent genius, but it isn't like there are two of him. Leave it to the humans to remember basic math. So it's just as well that she came back, really.
For practical reasons. Strictly practical.)
He blinks, finding himself right outside the TARDIS. He must have found his way there, even if he can't remember it.
Even as he's trying not to look back (didn't work for Orpheus, now did it?) his traitorous body turns, his head inexorably follows; all he sees is ruin. Shards of glass and bits of plaster and a lot of alien technology, decimated remains of Daleks and Cybermen. A lot of damage, a lot of blame to assign. But it's probably not fair to think unkindly about a dead woman, a woman who was converted into a Cyberman, at that.
Still. "If it's alien, it's ours"?
Bloody arrogant humans.
He starts the departure sequence at the console. Rather angrily, punching buttons and yanking levers harder than he needs to. The TARDIS likely doesn't appreciate it.
Might help to pay attention to his driving. Not that he knows where he's going just yet.
"So, where're we gonna go first?"
Eventually he makes the non-decision to float about in space, for now.
Of course he isn't going to try to go through. Of course. He isn't completely mad, after all; he knows it's impossible.
Unless it isn't. He's been wrong before.
If only he could be sure, somehow, that she made it.
Of course she made it. Unless she didn't.
Probably he should stop checking the readout for anomalies. The TARDIS will let him know if she finds anything. It's like waiting for water to boil, watching it just mucks with time. At least, it does on Solgauda IV, where the batlike inhabitants' sonar vision delays the excitation of water molecules, keeping the planet in a constant state of almost-ice...
A vision pops into his head unbidden then, a sudden memory-flash of Rose stepping gingerly into the ice-stuff for the first time, looking uncertain and excited all at once...
And he remembers the look on her face when she popped back into this reality, away from the other universe and the safety it brought, the life in comfort with her family and the ready-made fortune just waiting for her—how on earth (or outside it) could she be foolish enough to choose him over a life like that?
At the time he didn't want to think why she would choose him; refused to admit to himself that he would have done much the same.
"How long are you going to stay with me?"
He would find her, or she would find a way back to him, because he was the Doctor, and she was Rose, and that was just what they did. There was always going to be a way.
Was. Pesky past tense.
The TARDIS lets out a small chirp. He checks the readout, but it's just an ion storm.
He waits.
Some time later, he's found it, the one last small crack between the universes. It's too small for the TARDIS to slip through, unfortunately. He figured that would be the case.
He bites back bitter disappointment. This is not what he wanted. But he'll be damned if he lets the opportunity go to waste.
He quickly determines that if he can just boost the signal enough, he can get at least get some kind of a message through. It will take an enormous amount of power to get any kind of signal through to the other universe. A scary lot of power. But she's worth it.
"You just leave us behind. Is that what you're going to do to me?"
No.
There, close to the coordinates where the TARDIS has located the breach. A dying star, letting off a pretty enormous amount of power by the looks of it. Maybe even a scary lot of power.
He speeds the star's dying process along.
He tells himself it's a mercy killing.
He doesn't know what he's going to say.
He checks a few settings on the TARDIS console. Everything seems good and normal, considering the fact that she's currently in the process of blowing up a star. The TARDIS doesn't normally care to do work like this, would normally pitch a fit and send him sailing through the Vortex, but the Doctor can tell she's making an exception for Rose.
He pats her dash affectionately. Good old girl, she is.
Now to boost the signal through the positron energy matrix.
The loneliness hits him like a punch to the hearts. Technobabble doesn't sound nearly as fun when he's not saying it out loud to someone.
What can he say? He has to give some sort of goodbye to Rose.
"Now, forget me, Rose Tyler."
Of course, that's only if he can find her. He can't hope to just pop up in parallel London close enough where she can see him. He was lucky to be able to aim at Earth at all, really. Without a psychophysical trace to lock onto, contacting her from this universe would have been impossible. Fortunately she's left some things on board that will do the trick—some shoes, a shirt, a tennis ball for some unfathomable reason.
"Oh, we're flirting with international Olympic tennis players from the future now, are we?"
"Really, Doctor? First you're jealous of a cat, and now an autograph..."
"What? I've never been jealous a day of my life. Well, this life, anyway. And I have no idea what you're on about, cat-wise."
The shirt has minute traces of her on it, mostly hair and skin cells. Maybe not the most glamorous method of reaching her, but it will have to do.
As always, the TARDIS comes through.
He needs to bring her to him, or as close to him as possible. He calls her name, projects it to her using the telepathic signal of the TARDIS, wills her to come to him.
"Rose."
He waits for a little while, a day maybe, before the TARDIS feels her approaching. He hurriedly pulls a lever here, twists a crank there, and aims his sonic at the comm screen. His hearts thump in his chest, each pulse fresh and sharp, and he suddenly finds himself wishing he'd rehearsed for this or something.
Does time always move this slowly?
He presses the button on the screwdriver, says a silent prayer—to fake gods, bad gods, demi gods, would-be gods. Rose swims into view in his mind, a psychic image projected by the TARDIS. She's lit from behind, her hair fanning about her head in a wispy golden halo.
She looks lovely, but she also looks terrible.
"Where are you?" she asks.
There isn't much time.
"You look like a ghost." So does she.
He knows exactly what he needs to say.
"If I believe in one thing, just one thing—I believe in her."
Rose looks back up at him, struggling to regain a semblance of composure.
"I lo—" she starts, but the words are stillborn, strangled by thick tears.
The Doctor waits patiently, even hopefully, watching her, memorizing every last detail of her.
She tries again, looking everywhere but him, trying to find the obvious words, finding it so hard to say even now.
"I love you," she chokes out tearfully.
The Doctor is only slightly surprised to hear her say it. "Quite right, too," he says with a smile.
Rose nods back, smiling through her tears, running a hand through her hair again. He watches her for just a few moments.
He knows he needs to say something back. He needs to tell her. He wishes that they had more time. He wishes, not for the first time, that he'd rehearsed this.
But he knows exactly what he needs to say.
"And I suppose... if it's one last chance to say it..." he starts, but his voice tries to break, and he lets it.
He doesn't know why this is so hard to do. Rose looks up at him expectantly, glassy eyes brimming with tears. Her hopeful face inspires confidence.
If he's ever going to say it, to anyone, especially to Rose, now is his last chance.
"Rose Tyler..."
But he's alone on the TARDIS now. The image in his mind is gone. The connection is broken.
He realizes he's been crying. His face is cold and sticky where the tears have run down. He wonders when that started. He hadn't even noticed it.
The words he should have said to Rose burn in his head. He almost whispers them into the air, wondering if he should still say them. Wonders if it would be good for him to hear himself say them aloud, just to know that he is still capable of feeling such things, and maybe for the closure of it.
But as much as he hates it, and as much as it hurts, he doesn't want closure. He wants Rose, here with him, and the memory and the raw pain is better than feeling nothing at all.
The words die on his tongue.
Invisible walls are walls nonetheless.
There are the barriers between universes, the sometimes paper-thin partitions people construct between themselves and others, and there's a definite something separating "possible" from "impossible". Sometimes, when he's lucky, the Doctor can tear that something down. That's a good day. That's a very good day.
Today is not a good day.
Today he stands on a beach on a parallel earth a universe away, and thinks about the divides within oneself, and when oneself becomes twoselves, one of whom is wearing a blue suit and red Chucks and saying all the right things for once.
"Tell her…"
Rose pulls his duplicate in for a kiss.
"…oh, she knows."
The Doctor wants her to be happy, but does it really have to be like this?
(Of course it does. For once the universe can't be blamed; this was his own design, lovingly painted and signed with a flourish and sealed with a kiss that should have been his.)
Later, the jealousy will sour and fester in his veins, make him want to scream and tear, make him want to bend the timelines to his own will for once, just once, so that he can actually be a true lord of time instead of its bitter caretaker and servant. But right now, he just feels sort of hollow, watching another version of himself all-too-happily snogging Rose Tyler, knowing that the loneliness gnawing in the bottom of his stomach is only about to get worse when he and Donna return to the TARDIS. The upcoming task is one he wants to put off as long as possible, but he can't just stand there while a one-day-old copy of himself gets what he so desperately wanted, what he can't help but feel like he deserves.
He turns on his heel and leaves. He does not say goodbye.
He adds it to the list of the worst things he's ever done.