Idris: I'm the... oh, what do you call me? We travel. I go... (makes dematerialization noise)
The Doctor: The TARDIS?
Idris: Time and Relative Dimension in Space. Yes, that's it. Names are funny. It's me. I'm the TARDIS.
The Doctor: No, you're not. You're a bitey mad lady. The TARDIS is... up-and-downy stuff in a big blue box.
Idris: Yes, that's me. A Type 40 TARDIS. I was already a museum piece when you were young. And the first time you touched my console, you said...
The Doctor: I said you were the most beautiful thing I'd ever known.
Idris: Then you stole me. And I stole you.
The Doctor: I borrowed you.
Idris: "Borrowing" implies the eventual intention to return the thing that was taken. What makes you think I would ever give you back?
The Doctor: You're the TARDIS.
The Doctor: My TARDIS.
Idris: My Doctor. Oh, we have now reached the point in the conversation where you open the lock.