‘Can’t be easy.’ Chyll eased himself to the floor beside Rory, his skin grey and washed out in the half-light of his suit.

Rory didn’t say anything. He just chewed. Maybe he would get to like the taste. People could get used to anything.

Chyll waved his hand, indicating the dark corridor, the open cell, the wailing alarms. ‘I doubt this is anyone’s ideal Christmas.’

Rory shrugged. ‘I’ve had weirder,’ he said, before realising with a start that it was true. At least the whole thing with the space sharks had snow.

He had always wanted kids. Some nurses didn’t. Working in a paediatric ward could do that, sometimes. It was hard to see families on their worst days. On helpless days. On days when you could do nothing but say ‘I’m sorry’ over and over again. Rory had seen a lot of frightened parents in his time. Sometimes he thought that having a kid was like keeping your heart outside your chest – open, exposed, at the mercy of the world.

So you did little things. You put tinsel on ECG machines. You sprayed non-toxic snow on all the windows. You kept a smile on your face no matter what. You pretended everything was normal and the universe made sense, in the hope that you might somehow make it true.