HARRY: You recall how you took great pains to make sure we got back to London?

DOCTOR: Yes.

HARRY: Well, you didn't take quite as many pains to make sure it was the correct year.

DOCTOR: Ahh.

HARRY: Or decade.

DOCTOR: Ooh.

HARRY: Or century.

DOCTOR: Hmm. I suppose that does explain the youthful experience. Is it too late to say I'm sorry?

HARRY: It being too late is entirely the problem.