JO: Who is he and how did he get in here?

THIRD DOCTOR: Well it's a bit difficult to explain, Jo.

JO: He's not one of them, is he?

THIRD DOCTOR:: Well, not so much one of them as one of us. One of me to be precise.

SECOND DOCTOR: Oh no, no, no, no. I'm sorry, my dear, I hate to be contrary but I can see he's a little bit confused, poor old chap, and I do feel you should have the correct explanation. You don't mind, do you.

THIRD DOCTOR:: Yes.

SECOND DOCTOR: I didn't think you would. You see, Jo. I may call you Jo, mayn't I? You see, he is one of me.

JO: Oh, I see. You're both Time Lords.

SECOND DOCTOR: Well quite. Well, not quite.

JO: Oh.

SECOND DOCTOR: Not, not just Time Lords. We're the same Time Lord.

THIRD DOCTOR:: Now please, you're only confusing my assistant. Jo, it's all quite simple. I am he and he is me.

JO: "And we are all together, goo goo ga joob?"

BRIGADIER: I'm delighted to hear it. Make yourself at home. We're only supposed to be a top secret security establishment. Liberty Hall, Doctor Tyler. Liberty Hall.

(The Brigadier leaves.)

DOCTOR: Well, Sergeant, aren't you going to say it that it's bigger on the inside than it is on the outside. Everybody else does.

BENTON: It's pretty obvious, isn't it? Anyway, nothing to do with you surprises me anymore, Doctor.

DOCTOR: Oh, thank you for the compliment.

FIRST DOCTOR: Ah, there you are. I seem to be stuck up here. Hmm? Hmm? Oh, so you're my replacements. Huh. A dandy and a clown. Have you done anything?

SECOND DOCTOR: Well, we've, er, assessed the situation.

FIRST DOCTOR: Just as I thought. Nothing.

THIRD DOCTOR: Well it's not easy, you know.

SECOND DOCTOR: If only I could find my recorder, I could play you a little something to pass the time.

BRIGADIER: We must be thankful for small mercies.