Nikki isn't sure if it's the rough hands forcing her head underwater, or the shock of the cold that knocks all the breath out of her body.
Probably a combination of the two.
It takes a second for the panic to set in.
It had started the day before yesterday – a phone call at the crack of dawn with the news that a dog walker had found a dead, naked body in the local park.
A woman in her twenties, blunt force trauma to the head and numerous defensive injuries to half of her body, none of which presented an obvious cause of death at the scene. Until they got her back to the lab, and found froth in both her upper and lower airways, and emphysema aquosum, her lungs hyperinflated and froth again burst free when cut open, indicating drowning as cause of death.
However the lack of debris, silt or sand, found within her airways alongside the fact that the water had no traces of soap or common pool chemicals meant it was likely she had neither drowned in a natural body of water, nor anywhere domestic or recreational. The working theory was a paddling pool, or similar "clean" open water.
The ID had come quickly – Sophie Hall, twenty four years old, reported missing three days earlier by her mother. Her nineteen year old sister, Lucy, had vanished at the same time.
There was still no sign of Lucy.
Nikki blinked hard, forcing her eyes to remain open even in the darkness and the cold. To close them felt like giving up, and she was going to do anything but.
Her fingers scrabbled along the outside of the rainwater collection tank – not a paddling pool after all – nails clawing desperately against the plastic in an attempt to gain purchase and force her attacker off her.
But there's a hand on the back of her head forcing in down, the second in between her shoulder blades – and hunched over the tank, the edge digging painfully into her chest, she doesn't have any leverage either.
They were on their way, she just needed to last a little bit longer.
He wasn't a sophisticated killer.
That much became clear pretty quickly into the investigation – relying on his fists far more than his brains. Sophie was covered in DNA, all they needed was something to match it to.
Forensics had got them part way there, interviews and CCTV and good old fashioned police work the rest of the way, and they had a suspect. A very strong suspect, for whom they already motive and means and a very definite lack of alibi.
It was pure chance that Nikki arrived at the scene first – there were very clear instructions given to wait. DS Wallace would be there in just one minute or possibly two or five, but she was on her way with Harry in her front seat (it had been at the crime scene they made their final connection, and a stroke of good luck he was there as well), alongside the rest of the people who have the actual job to go into dangerous places and deal with dangerous people.
But there'd been a scream. Someone was terrified, and Sophie Hall only had defensive injuries down half her body because she was using her other half to keep her sister safe.
Sophie Hall hadn't died to keep her sister alive only for Nikki to sit and wait and listen to her get murdered anyway.
She'd already been underwater for thirty seconds at least, her lungs beginning to feel tight. Trying to arch her back, thrash in any way that would give her just a second to breathe, just a second to order her thoughts and figure out what comes next.
She must struggle more than he's used to – Sophie had been beaten and half dead before he gets them anywhere near the tank, Lucy looking the same way – because he steps even closer. Nikki can feel the rest of his body pressing unbearably tight against her, stopping her from moving.
She tries to kick but her legs are bracketed by his. She claws out and catches something, arm or torso or face she has no idea – but she has his DNA under her finger nails now.
They'll prove it with the DNA she thinks, before realising that she'd have to be dead in that scenario, and keeps fighting.
It doesn't help.
She's trapped.
She had been too late anyway – by the time she made it to the source of the screaming, it had stopped.
Lucy Hall lay motionless on the ground, blunt force trauma to the head to match her sister's, blood spreading, mixing with the water displaced from rainwater tank, turning the ground into a bloodied, watery mess.
She had been too late anyway, but Nikki still had to try and help her.
The man left, just for a moment, and she took her chance.
She'd gotten as far as trying to take a pulse, the chest unmoving and the eyes, half open and completely blank – when there was another scream, not of terror, but of anger, deep and male, followed by a hand fisting in her hair, dragging her backwards and upwards.
She didn't get a chance to scream herself before the water overtook her.
She'd been the one to perform the autopsy on Sophie Hall.
She's forgotten exactly how many autopsies she's performed on victims on drowning over her career – buckets, bathtubs, pools, rivers, lakes and seas.
Natural deaths, accidental deaths, suicides and homicides. She's seen a three year old, missed by her parents and the lifeguards in the local pool. She's seen an eighty six year old, who fell asleep in the bath and never woke again. She doesn't remember them all, she can't, but she remembers the steps.
She'd missed the pre-submersion phase, where she would have held herself above water under fatigue set in and she couldn't any longer. It's the submersion phase she's stuck in now – water covering her nose and mouth, blocking her airways leading to voluntary apnea. When needed, most people can hold their breath for thirty to ninety seconds, longer with preparation, shorter with shock or panic or fear.
By that point they won't be able to continue their state of voluntary apnea, the amount of CO2 in their body reaching a breakpoint and forcing them to take a breath involuntarily. If their head is above water, this leads to the inhalation of air. If their head is still submerged, it's the inhalation of water instead.
Water and debris enters the airway. If they've swallowed alongside inhaling the water, sometimes they vomit simultaneously. Relaxation of the larynx leads to further inhalation of water.
Anoxia sets in soon after, with the deterioration of brain function, loss of consciousness and finally irreversible neuronal cell injury.
It takes four to six minutes.
And even if they're found, even if they're discovered and resuscitated, the hypoxia can still trigger cardiac arrest, can still lead to respiratory and metabolic acidosis, multisystem organ failure and death.
Do everything right and they can still die.
Find her in time and she could still die.
She's lost track of the seconds but it's definitely over a minute by now.
Hypoxia and hypoxemia starting to set it, the point is coming soon – very soon – where she won't be able to voluntarily hold her breath any longer.
Her lungs burned.
She had to breathe.
The water rushing into her lungs burned like nothing ever had before, her whole body jerking underneath his hands as she fought for air.
They shouldn't be allowed to perform her autopsy – too close to it, they'll insist.
But maybe that's exactly why Harry and Leo won't let anyone else do it.
They're all too close.
She remembers Holly, poor murdered Holly, who they'd only known a handful of days before they were cutting her open on the slab.
It'll be worse when it's her. Not that they'll show it of course.
They'll be stoic and manly and not shed a single tear and inside they'll tear themselves up. Maybe she's thinking too much of herself. They'll be upset sure, but they'll get over it. They'll move on. And she'll still be dead.
She knows what he did to Sophie after she died, how he disposed of Sophie, the list of post mortem injuries almost as long as the ante mortem. Can list in almost macabre detail everything that will come next.
They'll find her, soon probably, they were already on their way. He won't have time to get rid of both corpses, so chances are he'll just leave them where they lie, take the opportunity to escape.
They'll find her, face down in the water, cold and still. DS Wallace will know immediately, but it's Harry, who spends his days surrounded by death, who'll refuse to admit it.
He'll pull her out, soaking wet, bleeding and bruised. They don't have much use for CPR in their line of work, patients usually too far gone for it by the time they get anywhere near them, but he'll try.
He'll keep going even as she's broken and bleeding and cold and dead, he won't give up until he's forced to, she knows that much for certain.
They'll get him off her eventually, but he won't leave her, won't trust her to anyone but himself until Leo arrives and he can trust her to Leo.
Then there will be the collection of trace evidence, the x-rays, taking her home to the Lyell for the last time.
The external examination, and at least she won't be herself anymore when she lies naked in front of all her colleagues, before moving to the internal, discovering every hidden secret she concealed within herself her entire life.
They won't let Harry do that, not with her blood still on his hand, but Leo, no one can stop Leo. He'll keep her safe even when she's not herself any more.
She knows the tests they will run on her, the very same tests she has run so many times, the tests she ran on Sophie Hall just yesterday.
She can see the forms they will complete, the narrative reports and the diagrams and the photographs.
There'll be a court hearing and a sentencing, a funeral and a burial. People will cry but not the right people, they'll say 'too young', 'too soon', 'too terrible', and they'll give their condolences and they'll move on with their lives.
And she'll still be gone
It doesn't hurt anymore.
It should but it doesn't.
She can't see in the dark of the tank, but feels her vision going black at the edges anyway.
Her fingers continue to scratch against the edge of the tank but it's sluggish, her actions slowing without any oxygen behind them – she can't even feel her finger tips anymore, a numb sensation running down her fingers towards her hands, towards her arms, towards her heart.
Her legs go limp, and the body that had been bracketing her, forcing her into stillness is suddenly the only thing that's keeping her upright.
The pain in her chest is fading. The pain in her head is fading.
She's fading.
She tries.
One last burst of energy, a kick, a scratch, one last something to try and get one more breath into her body, fighting and forcing herself to hope that this wouldn't be the last fight of her life.
But he's immovable, uncaring.
She takes a second breath, as involuntary as the first, and succeeds in nothing more than forcing more water into her lungs.
Not like this.
She thinks of home. Of the Lyell, of Leo, of Harry.
And then there's nothing.
Pain. Something pressing on her chest too hard. A snap somewhere deep.
And again. And again.
A hand cupping her cheek, rough, tilting her head back, forcing her jaw open, and then lips pressed against her own.
Warm air forces its way down her throat, pushing into her lungs, expanding them.
It hurts, and she tries to move away from the feeling.
But she can't get it off her, can barely move at all.
The pressing comes back and she wants to scream, cry, escape, something.
Please stop it hurts please please please.
"No... don't you dare do this to me!" It took a moment to place the voice, scratchy and rough and more terror than she's ever heard bleeding into the words, and then lips were on hers again, more air, then more pushing and her body jerked, mouth still open, and her throat burned as bile and water forced its way out of her throat. "You're not leaving me...not like this."
Someone rolled her over onto her side, stroking her back as she choked and it all came up, gasping for air in between gags, tears dripping from her eyes at the pain. It hurt so much...but she couldn't stop, retching long after she'd emptied both her stomach and her lungs of their contents.
"There you go...there you go," he spoke softly, a gentle hand on her back, relief imbuing every word. "It's okay. Let it out. You're safe."
She opened her mouth, tried to talk but all that came out was more coughing, more bile, more pain.
"Don't talk yet. Just breathe." She did, deep breaths of someone convinced they would never get the chance to breathe again, eyes snapping open as she found herself pulled into a lap, shivering hard.
Her head found it's way into the crook between his shoulder and his neck, as his arms wrapped tightly around her – better than a blanket would have been at banishing the cold from her frame.
Only now, surrounded by Harry, with him there to keep her safe, did she fully realize how close she had come to never hearing that voice again, no more late nights and early starts and no more lab, no more arms wrapped tight around her keeping her safe. Her lip began to tremble with something other than the cold that had settled over her, tears threatening to mix with the wetness already coating her cheeks.
There's a commotion happening in the corner, a veritable army of paramedics surrounding the ventilated and stabilised body of Lucy Hall, the girl obviously less dead than Nikki had briefly assumed before her own brush with the water.
Focusing her attention back on Harry, he looked exactly like he always had but different.
Sitting on the ground, with his clothes now water logged, bloodstained and muddied, holding her against his chest. He was shaking too, eyes filled with equal measures of terror and relief and glued to her, not daring to look away for a second.
"Harry?"
He shook his head, stroking wet strands of hair off her face. "What happened to don't talk yet?" he tried for light-hearted but it got lost somewhere amongst the terror still audible in his voice, his own shaky breath, the way he didn't want to drag his eyes away from her for a second, checking her over for some injury he might have missed.
She had scared him, as much as she had scared herself. The knowledge formed a pit inside her.
"Sorry." She tried again, rasping, throat burning, lungs protesting her use of them now that she was both breathing and talking again.
She wasn't quite sure what she was sorry for – not waiting, going in alone, nearly dying, throwing up on him – any and all of the above.
There's a moment of silence that stretches out and wraps around her almost as tightly as his arms, as they both struggle to remember how to breathe, their breaths syncing up slowly.
Harry is the one to break the rhythm with a heavy sigh, turning his head to press his lips to Nikki's wet hair. "That was too close," he said, low enough that she wasn't sure if she was supposed to hear it, tightening his hold on her as if to reassure himself that she was still there. "When I saw you, I thought…"
She trembles again when he can't bring himself to finish the thought out loud. It was bad enough that he had barely arrived in time, but the image of Harry having to pull her lifeless body from the rainwater tank, or finding her left in the woodlands like Sophie had been left, made her blood run cold. "Me too," she whispered. It was a gross understatement, but she squeezed him back to make sure he understood. "I'm glad you were here."
There's a deep sigh above her, and lips press into the top of her head once more.
They'll have to move soon. The paramedics are already starting to look antsy, and even Nikki isn't going to try and argue with a visit to the hospital.
There's a deep exhaustion spreading throughout her body, an ache in her chest that's only getting worse with each passing breath, and between the water and the vomit her throat hurts every time she breathes, let alone tries to talk, and the inevitable nightmares she can already feel building around her.
But for now, in this moment, in the damp and the dark and the dirty with Harry's warmth wrapped around her, she's home.
