This episode opens with a very fourth wall breaking speech by an older looking Ian Chesterton. He's talking directly to the audience, explaining that he and Barbara don't often tell people what happened, because they'd think them mad, but he thinks you could handle it. He opens up with talking about the Doctor, and very neatly, I think, sums up what Doctor Who is all about.
"The Doctor... He was old, when I was young. Somehow I still feel he's up there in his lunatic ship, righting wrongs, still specializing in trouble. He dives in, and usually finds a way out. He showed me so many things, so many...caught up in history, as the old boy tried to find our way home...it sounds ridiculous, fantastic. Well, it was a fantastic adventure."
