‘Hurry! Damn it, Ernie, do something!’ That was Sofia, a shrill, panicked scream this time. And it was just a little bit further away. I realised I hadn’t heard Crawford get into the truck. It dawned on me that he wasn’t stopping Erin so he could chivalrously rescue me himself, he was stopping her altogether. I looked up from what I was doing with the strap to see that all three were getting smaller by the second. Then I realised all the straps were back to hanging vertically. Gravity was back to normal. The inertia in my stomach ebbed, indicating that the truck had come to a stop.

That should have been good news. Except I knew the truck hadn’t outrun Sofia, Erin and Crawford. They had stopped chasing it because it wasn’t safe to go any further. They’d run out of time.

Which meant that I was now trapped in four tonnes of metal, in the middle of the frozen lake.

I’ll spare you the dishonest suspense of gently creaking ice and spider-web fractures on the surface: the truck sat for less than five seconds before it dropped several metres with a jolt and settled at a thirty-degree tilt. The cab, to my back, had gone in first. Another lurch, and the whole thing was at forty-five degrees. I knew I had to think of something, and fast.

A kernel of a plan formed. I flung the heavy buckle as hard as I could, but I gave it too much air and it clanged off the still-half-closed door and slid back to me. On my next try, I slid it across the floor; it skittered along before sliding out the gap. I wasn’t expecting it to catch on anything that would hold my weight – the lake’s surface was barren – but I wanted something on the surface. If I went under, my main concern was finding the hole in the ice again. If I didn’t pull on the strap, unsecured as it was, I could possibly follow it up to the surface. The walls were groaning from the outside pressure of the water. I could hear dripping, and I could smell the cold. I’m not sure, but I may well have been under the water line at this point. I gripped the chrome handle of the coffin with my good hand, ready for what came next. I would only get one shot.