The Doctor: They're not doors, they're walls. Walls that look like doors. Dor-wals, if you like, or dwalls. Walds, even. You fully got it when you said they're not doors. I mean, windows are... right. Big day for a fan of walls.
Rita: It's not just that. The rooms have... things in them.
The Doctor: Things? Hello! What kind of things? Interesting things? I love things, ask anyone.
Rita: Bad dreams.
The Doctor: Well, that killed the mood.