And even now Phyllis knew too much. The fact that he had such a good false ID implied a whole infrastructure that up until now had been hidden. Once they knew of its existence, they could probably ferret it out. Hiroko, Desmond, Spencer who was deep in the system in Kasei Vallis, all exposed . . . Nirgal and Jackie, Peter, Ann . . . all of them. Because he had not been clever enough to avoid a stupid awful woman like Phyllis.

He looked around the men’s room. It was the size of two toilet stalls, one stall with a toilet, the other with a sink, a mirror, and the usual wall of dispensers: sterility pills, recreational gases. He stared at these, catching his breath and thinking things over. As plans tumbled in his mind he whispered instructions to the AI in his wristpad. Desmond had given him some very destructive viral programs, and he plugged his wristpad into Phyllis’s, and waited for the transfers to take place. With luck he could crash her entire system: personal security measures were nothing against Desmond’s military-based viruses, or so Desmond claimed.

But there was still Phyllis. The recreational gases in the wall dispenser were mostly nitrous oxide, in individual inhalers containing about two or three cubic meters of gas. The room was, he judged, about thirty-five or forty cubic meters. The ventilation grill was next to the ceiling, and could be blocked with a strip of the towel, on its roll by the sink.

He stuck money cards in the dispenser and bought all the recreational gases in it: twenty little pocket-sized bottles, with nose-and-mouth masks. And nitrous oxide would be slightly heavier than Burroughs air.

He took the little scissors out of the key compartment on his wristpad, and cut a sheet out of the continuous roll of towel. He climbed onto the toilet tank and covered the ventilation grill, stuffing the sheet into the slits. There were still gaps, but they were small. He climbed back down and went over to the door. There was a gap at the bottom of the door, almost a centimeter tall. He cut some more strips from the towel. Phyllis was snoring. He went to the door, opened it, kicked the gas bottles out and stepped out after them. He took one last look at Phyllis, prone on the floor, and then closed the door. He stuffed the towel strips under the door, leaving only a small opening at one corner. Then, after glancing up and down the hall, he sat down and took a bottle and shaped the flexible mask to the hole he had left, and shot the contents of the bottle into the men’s room. He did that twenty times, stuffing the empty bottles in his pockets until they were full, and then making a little satchel for the remainder out of the last strip of towel. He got up and clanked over to the cart and sat down in the driver’s seat. He stepped on the accelerator and the cart jerked forward, in a movement the opposite of the sudden stop that had thrown Phyllis off the back-seat and onto the floor. That would have hurt.