It’s now or never, then. I let my gaze go behind her. “No, don’t!” I shout. She doesn’t take the bait and look to see who I’m talking to, but she does hesitate for just a second—long enough for me to hurl the concrete chunk at her face. She jerks away, taking the impact on her forearm instead, and I scramble to my feet and flee.

I yank the poncho back down over the dials so Diaz can’t track me by its glow. I hold my injured hand out, following the wall on my left. There’s cursing behind me and then several loud splashes in quick succession. She’s coming after me, and she’s pissed.

I feel a break in the wall, a gap barely big enough for me to squeeze the transmitter through. It’s a shortcut—a dangerous one—but I’ll have to take it. I shove myself in, trying to be as quiet as I can. The walls here are bowed in by pressure. Too many of the supports have snapped and the earth weighs heavy on the remaining ones, ready to cave in entirely if another of them breaks.

The pain in my hand intensifies. I grit my teeth and try to breathe through it the way Dr. Washburne taught me to breathe through my anxiety. It helps, but only a little.

I count the supports as I go, feeling the rotted wood graze my fingers. Three. Four. Five. I pant with the effort of not crying out. Just a few more … and then I’ll … I’ll turn off into the tunnel leading to my loft—maybe she’ll be far enough away that she won’t hear by then—

Agony lights up every cell, fingertips to collarbone, a writhing supernova of pain. My veins feel alive. They’re snakes beneath my skin. Venom drips in their wake, eating through my body like acid. I gasp in a breath and hold it, clamping down on myself, my vision blurring with the effort of staying silent. I can’t stay on my feet. I fall sideways against the wall, then to the ground.

I curl around the transmitter. I scream.

Through the haze of agony, I hear footsteps. Diaz heard me. She’s coming through the side tunnel after me. I’ll be caught. I’m doomed—we’re all doomed.

My legs spasm. One of them catches a support beam. It shudders and the earth around me creaks and groans.

Diaz’s footsteps pause.

I have an idea. Something about—caving in, blocking the path …