DOCTOR: When we met, I said travel with me in space. You said no. Then I said time machine.
ROSE: It wasn't some big plan. I just saw it happening and I thought, I can stop it.
DOCTOR: I did it again. I picked another stupid ape. I should've known. It's not about showing you the universe. It never is. It's about the universe doing something for you.
ROSE: So it's okay when you go to other times, and you save people's lives, but not when it's me saving my dad.
DOCTOR: I know what I'm doing, you don't. Two sets of us being there made that a vulnerable point.
ROSE: But he's alive!
DOCTOR: My entire planet died. My whole family. Do you think it never occurred to me to go back and save them?
ROSE: But it's not like I've changed history. Not much. I mean he's never going to be a world leader. He's not going to start World War Three or anything.
DOCTOR: Rose, there's a man alive in the world who wasn't alive before. An ordinary man. That's the most important thing in creation. The whole world's different because he's alive.