The Doctor: I'm sorry, I didn't know. You have to believe me. They're better than this.
Ambrose: This is our planet!
The Doctor: We had a chance here.
Ambrose: Leave us alone!
The Doctor: In future, when you talk about this, you tell people that there was a chance but you were so much less than the best of humanity.
The Doctor: There are fixed points through time where things must always stay the way they are. This is not one of them. This is an opportunity. A temporal tipping point. Whatever happens today will change future events. Create its own time line, its own reality. The future pivots around you, here, now. So do good. For humanity, and for Earth.
Amy Pond: Right. No pressure there, then.
The Doctor: Okay. Bringing things to order. The first meeting of representatives of the human race and homo reptilia is now in session. Ha! Never said that before. That's fab. Carry on.
[Elliot has just been awakened from artificial slumber]
Elliot: But where are we?
Mo: Well, I've got to be honest with you, son. We're in the centre of the Earth, and there are lizard men.