Everything I touched, snapped. In the pitch black it was impossible to tell the bones apart. My shoulders scraped the sides clean, sending a shower of osseous matter down into the cavern below. I wedged my back against the wall and pushed up with my feet, bracing, scrabbling, pulling with my fingertips where I could. Unknown lumps of skeleton fell from Baaz’s own scramble out, hitting my head, shoulders. I was at the bend now. The chimney constricted. My eyes clogged with dirt and dust. My nails bled; my face was scratched red raw. I paused to catch my breath, and tasted for the first time in hours the cool sweetness of fresh air.

I was nearly there.

‘OK, I’ve done it. Bloody hell.’ It was Baaz calling from above. By the sound of it he was out. ‘It’s tight, but I think you can make it.’

‘Good,’ I yelled up. ‘Run. You hear me? Run, and don’t look back.’

If he got busted, he’d be screwed. If he got busted with me, he’d be dead. I rested my right hand on the pistol grip of the M4 and cursed the stupidity of carrying it up with me. But as I looked down and braced myself for the last push up and out, the air filled with the pulsating boom-roar of a grenade blast. I looked down. A rifle-mounted torch probed the bone-pipe. The chute flooded with light.

Shit.

The white faces of the dead pressed in on me. If you’re going through hell … keep going. So I breathed in and pushed for all I was worth against the walls. But my shoulders would not move.

I was a dead man.

Do something. Or do nothing.

I tucked my chin in, squeezed my legs together, folded my arms across my chest. And dropped.

The frozen faces fell away in a helter-skelter frenzy of bone-blurred descent. The minutes taken to inch my way up took seconds to reverse. As I landed hard, a man’s head poked into the opening. My feet found his shoulders, pushing him back and out, exiting at speed in a slimy skull-wave of broken bones that plunged us back into the charnel house together. I picked myself up. He was heavyset, black combats, tactical vest. Two twenty, two thirty pounds. And out cold. His body was half buried by the skull-slide, partly lit by the rifle light wedged tight beneath him. His face was covered by a military respirator. Could have been a cop. Could have been whoever the fuck else was after me.