Welcome aboard

The Doctor: Ah. Right. Yes. Bigger on the inside. Do you like it?

Wilfred: I thought it’d be cleaner.

The Doctor: Cleaner?! I could take you back home right now.

Wilfred: Listen Doctor. If this is a time machine, that man you’re chasing. Why can’t you just pop back to yesterday and catch him?

The Doctor: I can’t go back inside my own timeline. I have to stay relative to the Master within the causal nexus.

The Doctor: Understand?

Wilfred: Not a word.

The Doctor: Welcome aboard.

Wilfred: Thank you.

— “The End of Time, Part 2”, Doctor Who