Question: SPOILER If, by the end of the movie, the facility was reprogrammed to have all doors unlocked on a power failure - and there was a sudden power failure when Domhnall inserted the card into the computer terminal... Why did he remain locked within? Shouldn't he be set free by the programming change he freed Ava with?
Answer: The "Red glow" was the emergency lights that had come on every other time the power went out. And the final power outage was orchestrated by previous arrangement by the robot and Caleb.
Chosen answer: He inserted his own card in Nathans computer. Also, there was no mention of a power failure, only a red glow. This would be a different event than he's programmed the system for.