The Pale Lady ran up another short flight of stairs and into a dark noisy cavern full of flashing lights. An electric-blue neon sign over the entrance said WELCOME TO FUNLAND.

It was packed, mostly teenagers and young men who were killing time before the clubs opened. They were playing slot machines and old-fashioned racing games that I remembered from ten years ago. If the Pale Lady had gone to ground among all those bodies I might have lost her. But either she was on a timetable or she was smart enough to know that the wrath of the Metropolitan Police was about to fall on her from a great height. Nobody kills a suspect in a police station and gets away with it—at least nobody without a warrant card.

Amid the games and slot machines two escalators led upward to the next floor. When I saw a teenage boy pointing and his mate pulling out his phone to film something out of my sight I knew the Pale Lady was going up that way. I’d already spotted that if I jumped onto the Skittles machine I could jump again high enough to grab the escalator rail and vault onto the steps. I landed just short of the Pale Lady, riding up lying flat on her back to stay hidden. She hissed and lashed her foot at my face but I got out of the way in time to hear her heel go past my ear with a sound like ripping silk. I reared back and tried to stamp on her other knee, but she scrambled back and tried to kick me in the bollocks. I twisted and her kick grazed off my thigh, but hard enough to stagger me. She was just about to kick me again when we reached the top of the escalator.

She screamed and I realized that her hair, as short as it was, had caught in the metal teeth at the top of the escalator. She thrashed, did a sort of roll and then a desperate headstand to pull it clear. I grabbed my baton, extended it, and lashed down as hard as I could. I didn’t think I’d get a second chance like this.

They train us to use our batons, you know. They don’t just issue them to us and say “Try not to kill anyone.” There are light taps for warnings, a full arm swing that’s deliberately slow to make your suspect flinch back, the sneaky slap to the thigh that isn’t easy to see on the news footage. But the basic principle is that the amount of force is always controlled and appropriate. This is why I lunged forward while she was upside down and hit the Pale Lady in the hip with everything I had. Something crunched under the baton and she howled loud enough to cut through all the music and sound effects. Then she kicked me in the cheek.