John's first attempt goes fairly badly, and he is locked up in 'the hole' where he is burned by the sun. then frozen, in rotation for a number of days.
His buddies realise that the cameras are never on, but his buddy hacks the frequency of the cell TV to show them that the implants are attached to their own optic nerve - sending images back to the main computer. His buddy manages to rewire a system, so they can plan their escape while keeping the guards busy.
First, Brennick approaches the Russians. He knows they have a spaceship waiting, and he promises to create a diversion so they can escape if they let him tag along. They attach a video camera to a cockroach, who scuttles along the corridors and they spy on guards punching security codes into doors.
The resistance fighter with the dodgy implant gets through the first few barriers and opens the doors for the others. They manage to disable the computer's security system, and the Russians hurry to the spaceship - but they kill the spy in Brennick's team and leave the good guys behind. As they are leaving, a laser from the prison facility takes out the spaceship.
The warden catches up the Brennick and his crew, and before they kill him he damages an air-lock and (while holding his breath, of course) jumps out into space and safely lands on another part of the station. He leaves open the door on the other end, which causes all manner of problems for the ship's computer.
Meanwhile the Warden has a fight with the computer, and the whole station starts to close down. Sato, the cruel prison guard, catches Brennick. The good guard comes to his aid, but is hit with a lethal charge. Brennick and Sato fight, and Sato is soon sent out another air-lock.
The station is starting to fall apart, with explosions and sprinkler systems everywhere. The prisoners board the last remaining supply ship. The Warden catches up with Brennick, and the last remaining guard who betrayed the resistance fighters. The Warden shoots the guard, who in turn falls down a few levels and electrocutes the Warden.
Brennick just manages to make it into the supply ship, which detaches itself from the station and flies to safety.
Back on Earth he is reunited with his wife and son again in one of the quickest reunion scenes you'll ever see in a movie!