Try to rest on the mattress — it's been over 24 hours without sleep, and exhaustion is catching up fast.

I collapse onto the mattress without even taking off my shoes. The thin foam compresses under my weight, barely a barrier between my body and the cold wooden floor beneath, but it might as well be a cloud. Every muscle in my back and shoulders unknots at once, and the fluorescent buzz of the overhead light blurs into a warm hum as my eyelids drop. The last thing I register before sleep takes me is the rhythmic click-click-click of Razor's blade — slower now, almost meditative — and Viktor's low murmur into his phone somewhere near the kitchenette.

I sleep like the dead. No dreams. No twitching awake at strange sounds. Just a black void that swallows hours whole.

When I surface, grey daylight is leaking around the edges of the blackout curtains. The apartment smells of stale coffee and cigarette ash. I sit up slowly, blinking, my neck stiff and my mouth tasting like something crawled into it and expired. The monitor on the card table is dark — the subway feed permanently dead now. Razor is asleep on the floor near the door, his leather jacket balled under his head as a pillow, one hand still resting on the pistol in his waistband even in unconsciousness. Viktor is gone.

I stand, stretch until my spine pops in three places, and walk to the workbench they've set up along the far wall — smaller than the subway station setup, but the same basic equipment, supplemented with the leftover chemicals from my first batch. I pour myself cold coffee from a pot on the hotplate and drink it in four bitter swallows while staring at my handwritten notes.

The footage replays in my mind. Not the killing — I **** that aside — but the shudders. Three distinct tremors. The way her hand went to her shoulder. The clenched fist.

She felt it.

If the acid etched even microscopically into the diamond surface, and she responded with what looked like discomfort, that means there's a nerve analogue underneath. Or within. The crystalline structure isn't dead material — it's alive, it's her, and somewhere in that lattice there are pathways that register sensation. My compound scratched the paint, so to speak, and the scratch stung.

I set down the coffee mug and pick up my pen. The formula needs to change. Not stronger — smarter. Two phases. Phase one: a concentrated fluoride etchant that strips the outermost crystalline layer on contact, faster and more aggressively than version one. Phase two: a neuropathic agent — capsaicin was the right instinct, but I need something that hits harder once the surface is compromised. Oleoresin capsicum concentrate, combined with a DMSO carrier to **** penetration into any micro-fissures the etchant creates. DMSO carries compounds through biological barriers like they aren't there. If her diamond skin has even the faintest porosity once the top layer is etched away...

The idea crystallizes with a clarity that makes my hands shake. This isn't a weapon designed to kill her. This is a sensory bomb. Eat away the armor, then flood whatever's underneath with the most intense chemical pain stimulus I can engineer. Not lethal. Overwhelming.

I don't write this down in plain terms. My notes read like an iteration on the original formula — "increased etchant concentration, secondary irritant payload, improved carrier solvent." Anyone reading them would assume I'm trying to build a stronger version of the same thing. Viktor's people think I'm making a weapon. Let them think that.

"The fuck you doing already?" Razor's voice, rough with sleep, comes from behind me. He's propped himself up on one elbow, squinting at me with bleary irritation.

"Working," I say without turning around. "Unless you'd rather I take a vacation."

"It's barely morning, man." He drags himself upright, running a hand over his shaved scalp. "You're a freak, you know that?"

"I've been told."

He shuffles to the mini-fridge, pulls out a can of energy drink, and cracks it open. The carbonation hisses in the quiet apartment. He stands there for a moment, drinking, watching me work. Then, quieter than I've ever heard him speak: "That stuff you made. At the station. It actually did something to her."

"It did."

"So you can... you can actually figure this out? Like, for real?"

I turn to look at him. His narrow grey eyes are stripped of their usual contempt. What's left underneath is raw and young and frightened. He looks like what he is — a twenty-something kid who's in way over his head.

"I'm working on it," I say. Not a promise. Not a lie.

He nods once, sharply, and retreats to his corner.

The next two days blur into a rhythm of chemistry and sleeplessness. Viktor returns Friday morning with the additional supplies I requested — industrial DMSO, higher-grade hydrofluoric acid in sealed HDPE containers, pure oleoresin capsicum extract so potent that even the sealed bottle makes my eyes water when I hold it up to the light. He watches me work for a while, arms folded, asking no questions. He's smart enough to know he wouldn't understand the answers.

I build the new compound in careful stages. The etchant is reformulated with a higher fluoride concentration and a thixotropic gel base that clings on contact rather than running off — it'll adhere to her diamond surface like napalm and keep eating. The secondary payload is the capsaicin-DMSO mixture, microencapsulated in a polymer shell that dissolves once the etchant has had three to five seconds to work on the surface layer. Timed release. Strip the armor, then hit the exposed nerves.

By Saturday evening, I have six new canisters. Larger than the originals, heavier, with improved pressure valves for wider dispersal radius. I test the etchant on a piece of quartz crystal Viktor sourced from somewhere — within four seconds, the surface clouds, pits, and begins to flake. The capsaicin-DMSO mixture penetrates the micro-fissures and stains the interior of the crystal a deep amber. If her diamond form has any biological sensitivity at all beneath that surface...

Sunday morning. I'm recalibrating the timer mechanisms on the last two canisters when the apartment door bangs open. Viktor strides in, his leather jacket dark with rain, his expression carved from granite.

"Pack up," he says. "We're moving. Now."

I set down the screwdriver. "What happened?"

"She found this address. One of our scouts spotted movement near the building last night — someone casing the exterior. Could be her in her... normal form, whatever that looks like. Could be someone working with her. Either way, this place is burned." He's already pulling a duffel bag from the closet, shoving weapons and ammunition into it. "Basement on Willow Lane. It's the next safe house. Van's downstairs."

Razor is on his feet instantly, his blade out, checking the window through a crack in the curtains. "I don't see anyone out there."

"You wouldn't," Viktor says flatly. "She walked through a wall last time, Danny. She doesn't need to stand on the sidewalk."

I don't move from the workbench.

Viktor notices. He stops packing and turns to face me, his scarred jaw tight. "Did you hear me? We're leaving."

"No," I say.

The word hangs in the stale air of the apartment. Razor freezes by the window. Viktor's eyes narrow.

"What did you say?"

"I said no. I'm staying." I gesture at the workbench — the canisters, the beakers, the half-assembled delivery mechanisms. "I've got six improved canisters ready and I need to see what they do. If I pack all this up and set up in a new location, I lose a day minimum. Maybe two. And every time we move, she destroys the place and gets closer to the next one." I meet Viktor's stare directly. "I need to deploy these here. Watch what happens. Adjust the formula again based on results. That's how science works — iteration. Running doesn't help me help you."

Viktor takes a step toward me. He's a big man, and in the cramped apartment, he seems to fill the entire space. His voice drops low. "You understand what you're saying. She comes here, you're in the building. Those canisters don't stop her — and last time they didn't — you're dead. Brain out your nose. Head popped like a grape."

"I understand the risks."

"Do you? Because I've seen what she does up close, kid. I pulled what was left of Tommy Baretti out of the warehouse with a fucking mop."

"I understand the risks," I repeat, slower this time. "But if I keep running from hideout to hideout, I'll never get enough data to build something that actually works. At some point, somebody has to stand in the same room with her and see what happens. That's me. That's what you kidnapped me for."

Viktor stares at me for a long, grinding moment. The rain hammers against the window. Razor is watching us both with wide eyes, his blade forgotten in his hand, his mouth slightly open.

Finally, Viktor exhales through his nose — a long, controlled breath. "You've got balls, I'll give you that." He pulls out his phone. "I'll leave you four men. Armed. They won't last, but they'll buy you time to observe before you need to get out." He jabs a thick finger at my chest. "You watch. You take your notes. And when she starts killing, you run. There's a fire escape off the kitchen window. You use it. You do not play hero. Understood?"

"Understood."

He turns to Razor. "Danny. You're staying with him."

Razor's face drains of color. "Viktor — "

"That's not a request." Viktor's voice is iron. "He needs a pair of eyes watching his back while he watches her. You're it."

Razor's throat works. His knuckles are white around the handle of his razor. For a second I think he's going to argue, or bolt, or both. Then something in him settles — not courage exactly, but the resignation of a man who knows he has no other options.

"Yeah," Razor says quietly. "Okay."

Viktor nods once, grabs the duffel bag, and walks out. The door clicks shut behind him. The apartment feels smaller without him in it.

Razor and I look at each other across the dim room. Rain streaks the blackout curtains. Somewhere below, the van's engine starts and fades into the distance.