The exchange between the Doctors: Fifth Doctor: "Does he [the Master] still have that rubbish beard?", Tenth Doctor: "No, no beard this time. Well, a wife," is a pun. A 'beard' is a slang term for the wife of a gay man (who marries to hide his sexuality). The lesbian equivalent (husband) is a 'merkin'. See more
[the Fifth Doctor has mistaken the Tenth Doctor for a fan
What do you mean a fan? I'm not just a fan! I'm you.
Okay, you're my biggest fan. Look, it's perfectly understandable. I go zooming around space and time, saving planets, fighting monsters, and being, well, let's face it, pretty sort of marvelous. And naturally, now and then people notice me. Start up their little groups. That L.I.N.D.A. lot! Are you one of them?
[the Tenth Doctor looks sheepish
How did you get in here? Can't have you ...