slaves, the way you are a slave."
Tonker was shouting abuse at them that only Robbie could hear. He wanted to shut Tonker up. What business did he have being here anyway? Except for a brief stint in the Isaac shell, he had no contact with any of them.
"You think the woman you've taken prisoner is responsible for any of this?" Robbie said. The jets were three minutes away. Kate's air could be gone in as few as ten minutes. He killfiled Tonker, setting the filter to expire in fifteen minutes. He didn't need more distractions.
The Isaac-reef shrugged. "Why not? She's as good as any of the rest of them. We'll destroy them all, if we can." It stared off a while, looking in the direction the jets would come from. "Why not?" it said again.
"Are you going to bomb yourself?" Robbie asked.
"We probably don't need to," the shell said. "We can probably pick you off without hurting us."
"Probably?"
"We're pretty sure."
"I'm backed up," Robbie said. "Fully, as of five minutes ago. Are you backed up?"
"No," the reef admitted.
Time was running out. Somewhere down there, Kate was about to run out of air. Not a mere shell — though that would have been bad enough — but an inhabited human mind attached to a real human body.
Tonker shouted at him again, startling him.
"Where'd you come from?"
"I changed servers," Tonker said. "Once I figured out you had me killfiled. That's the problem with you robots — you think of your body as being a part of you."
Robbie knew he was right. And he knew what he had to do.
The Free Spirit and its ships' boats all had root on the shells, so they could perform diagnostics and maintenance and take control in emergencies. This was an emergency.
It was the work of a few milliseconds to pry open the Isaac shell and boot the reef out. Robbie had never done this, but he was still flawless. Some of his probabilistic subsystems had concluded that this was a possibility several trillion cycles previously and had been rehearsing the task below Robbie's threshold for consciousness.
He left an instance of himself running on the row-boat, of course. Unlike many humans, Robbie was comfortable with the idea of bifurcating and merging his intelligence when the time came and with terminating temporary instances. The part that made him Robbie was a lot more clearly delineated for him — unlike an uploaded human, most of whom harbored some deep, mystic superstitions about their "souls."
He slithered into the skull before he had a chance to think too hard about what he was doing. He'd brought too much of himself along and didn't have much headroom to think or add new conclusions. He jettisoned as much of his consciousness as he could without major refactoring and cleared enough space for thinking room. How did people get by in one of these? He moved the arms and legs. Waggled the head. Blew some air — air! lungs! wet squishy things down there in the chest cavity — out between the lips.
"All OK?" the rowboat-him asked the meat-him.
"I'm in," he replied. He looked at the air-gauge on his BCD. 700 millibars — less than half a tank of nitrox. He spat in his mask and rubbed it in, then rinsed it over the side, slipped it over his face and kept one hand on it while the other held in his regulator. Before he inserted it, he said, "Back soon with Kate," and patted the row-boat again.
Robbie the Row-Boat hardly paid attention. It was emailing another copy of itself to the Asimovist archive. It had a five-minute-old backup, but that wasn't the same Robbie that was willing to enter a human body. In those five minutes, he'd become a new person.
----
Robbie piloted the human-shell down and down. It could take care of the SCUBA niceties if he let it, and he did, so he watched with detachment as the idea of pinching his nose and blowing to equalize his eardrums spontaneously occurred to him at regular intervals as he descended the reef wall.
The confines of the human-shell were claustrophobic. He especially missed