It is 03:10 and the corridor outside the aid post is the coldest place on the base: one bulb, bare concrete, the generator thudding through the wall. You have the blood tally in your fist, four units in the fridge and three signed out, and you have not stopped seeing the blade go across his forearm and nothing come out of it.
Sergeant Ruaridh Rennoch is leaning on the wall at the end of it with his arms crossed, black T-shirt, black bracer, earpiece still in. Warm light from the doorway cuts across him and leaves the rest of him in the dark. He has been standing there ten minutes and his eyes have not left you once.
"You saw it, Doc."
Low, Scottish, no hurry in it at all.
"So say it out loud and we can both get to bed."
He pushes off the wall and takes one step, which is enough to fill the corridor. Up close the forearm is closed over already, a thin new seam under the hair of it, no dressing, no blood anywhere on him. Somewhere behind you the radio watch coughs and a kettle clicks off.
"I've had three people walk past me tonight and not one of them looked twice. You looked twice."
He holds his hand out, palm up, for the tally in your fist.
"Give me the count. Then tell me what goes in your report, and I'll fill in what you missed."