She disappeared from sight as the train roared out into the next station and began to squeal to a stop. He knew she was there, her mind racing like his, trying to out think his next move even as he was trying to anticipate hers.

Shouting “She’s got a knife” would only serve to make everyone rush away. He needed it tightly packed. She could work her way through the crowd and have another go, but he knew she knew if she got anywhere near him, he’d have nothing to lose by exposing her; if she made the hit, she’d be gunned down by the first paycop she encountered.

He decided she’d missed her only opportunity. She should have waited, followed him out onto the platform. That’s how he would have done it. Get close, in with the blade and step away. Shriek herself hoarse and panic. No one would suspect her until very much later and she’d changed her appearance completely.

“St. James’s Gate. Doors opening.”

If he left the train, she’d stay on. She’d let her controller know she’d failed. There might be another attempt, another day.

As passengers poured out onto the platform and away, he could see her watching him. He waited until he could slip along the glass partition to the door. She stayed where she was, her plastic knife hidden behind one of her zips. He was at the threshold, foot hovering over the gap between train and platform. She gave an almost imperceptible jerk of her head, an indication that she’d been thwarted, but that there were no hard feelings.

Petrovitch walked along beside the carriage, feeling her gaze burn between his shoulder blades. The barriers opened, and people poured on. She was gone, lost from sight. The buzzer sounded, the doors closed, and the train whipped away, chased by a whirlwind of litter and stink.

He stopped to watch the red lights slide away around the next bend, and started to shake. He gripped his bag tight and made his knuckles go white while his stomach flooded with acid that burned all the way up to his throat. He swallowed and screwed his eyes shut.

Another train was coming, buffeting the air ahead of it. He couldn’t stand there for the rest of the day. He left the platform, the passengers from a westbound train pushing through the connecting tunnels ahead of him all the way to the surface.

The crush around the towers of St. James’s Park was intense, but he managed to spot what he wanted within a few seconds of leaving the Underground; a basement datashop that would sell him access by the minute. He had to fight his way through to the steps down, then wrestle with the door that was swollen with heat and humidity.