Avery: (examining the TARDIS controls) What's this do?
The Doctor: That is very, very complicated. That does sophisticated. That does... whoa, amazing. And that does whiz, bang, far too technical to explain.
The Doctor: Atom accelerator.
Avery: It steers the thing.
The Doctor: No. Sort of. Yes.
Avery: Wheel. Telescope. Astrolabe. Compass. A ship's a ship.
The Doctor: Uh-huh.