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?"