In response to some earlier speculations about Cortana's possible rampancy, jds makes a good point.
jds (email@example.com) writes:
According to "The Fall of Reach," the life-span of "smart" AIs is seven years. The AIs don't die, rather they get to a point where they just spend all of their time thinking.
She is in no way just a ship's AI. She has no restrictions placed on her personality. No inhibitions when it comes to speaking her mind. She has only one mission: Help John, which she is naturally inclined to do. Remeber, she was created from Dr. Halsey's cloned brain.
So, what would Cortana rebel against?