With no interval to provide a margin for error at all, the drone shunted its personality from its own AI core to its back-up picofoam complex and at the same time readied the signal cascade that would transfer its most important concepts, programs and instructions first to electronic nanocircuitry, then to an atomechanical substrate and finally - absolutely as a last resort - to a crude little (though at several cubic centimetres also wastefully large) semi-biological brain. The drone shut off and shut down what had been its true mind, the only place it had ever really existed in all its life, and let whatever pattern of consciousness had taken root there perish for lack of energy, its collapsing consciousness impinging on the machine’s new mind as a faint, informationless exhalation of neutrinos.

The drone was already moving; out from its body-niche in the wall and into the companionway space. It accelerated along the corridor, sensing the gaze of the ceiling-beam camera patch following it. Fields of radiation swept over the drone’s militarised body, caressing, probing, penetrating. An inspection hatch burst open in the companionway just ahead of the drone and something exploded out of it; cables burst free, filling to overflowing with electrical power. The drone zoomed then swooped; a discharge of electricity crackled across the air immediately above the machine and blew a hole in the far wall; the drone twisted through the wreckage and powered down the corridor, turning flat to its direction of travel and extending a disc-field through the air to brake for a corner, then slamming off the far wall and accelerating up another companionway. It was one of the full cross-axis corridors, and so long; the drone quickly reached the speed of sound in the human-breathable atmosphere; an emergency door slammed shut behind it a full second after it had passed.

A space suit shot upwards out of a descending vertical tubeway near the end of the companionway, crumpled to a stop, then reared up and stumbled out to intercept the machine. The drone had already scanned the suit and knew the suit was empty and unarmed; it went straight through it, leaving it flapping halved against floor and ceiling like a collapsed balloon. The drone threw another disc of field around itself to match the companionway’s diameter and rode almost to a stop on a piston of compressed air, then darted round the next corner and accelerated again.

A human figure inside a space suit lay half-way up the next corridor, which was pressurising rapidly with a distant roar of gas. Smoke was filling the companionway in the distance, then it ignited and the mixture of gases exploded down the tube. The smoke was transparent to the drone and far too cool to do it any harm, but the thickening atmosphere was going to slow it up, which was doubtless exactly the idea.