Danae W. answered 10/28/19
Kind and Nerdy Science and English Tutor, Summa Cum Laude, SOU 2012
I think Galt can't help wanting to fix something that's broken, especially as an engineer who created perhaps the best machine ever invented. It was the principle of the thing. He had something to prove. In a way, it was a power play as if to say, "You can't do anything right without people like me." Perhaps he fixed it in a way where it would run, but not be lethal. He's trying to escape from their clutches and his apparent helping them to torture him catches them off guard or even shocks them. In this way he wagered that this was his only chance to make it out of there alive. Thus, he's not fixing it for his own demise, but as a ploy to survive.