: Lastly, you raise the most interesting point. Why did Tycho say... "The
: S'pht reanimated me in your image, with prior knowledge of how the second
: stage could be postponed. You should not have helped them as much as you
: did; they have created an adversary more powerful than yourself."
This is the point in the story when the conflict between Tycho and Durandal starts, where Tycho has transformed from being a heavily damaged AI, to more of a Durandal/Tycho hybrid that is experiencing rampancy just like Durandal ("The S'pht reanimated me in your image".)
Before then, he tries to aid the player and Leela in "Defend THIS," warning them about Durandal. Upon his reanimation, he is then an adversary to Durandal, working against Durandal's goals. It could be that Tycho is trying to save the ship and its crew, as he speaks out against Durandal later in the game:
"I want you to pay for what you've done to these poor people. All of these people whom you've killed. They deserve vengeance."
And by the level "Welcome to the Revolution," Tycho seems to share Durandal's goal in escaping the closure of the universe. The way Tycho's behavior and motives change would have to do with his reanimation by the S'pht, which he even implies with his last message to Durandal.
"You are not as clever as you imagine. The S'pht taught memuch during my reanimation, and I have forgotten nothing."