Red lights were flashing. “Security alert. Colonial police have been summoned,” chanted a mechanical voice.

Bates drove the floor-scrubber at the platform; panicking commuters jumped aside or got buffed. A tram had just arrived; he drove the machine off the edge of the platform behind it, leaping free at the last minute.

Bates ran inside the tram. An elderly man seated by the door was working a crossword puzzle. Bates snatched his pencil, pushed up the aisle and drove it into the driver’s right ear. He dumped the unconscious driver out of the seat, took it himself and stomped the accelerator. Nothing happened.

Three officers on hoverbikes pulled up at the tram’s center door. A bold passenger grabbed Bates by the shoulder; “Give it up, man.” Absently he smashed the man’s nose with his elbow and returned to studying the controls. Two officers piled in, forcing their way forward. Bates pulled a lever; the doors closed. The third smashed the glass with his baton.

The tram lurched forward.