The Empty Hearse DVD commentary:

Vertue: That’s a dreadful cup of tea!

Gatiss: I know, so thin.

Vertue: She should be ashamed it’s too thin.

Moffat: Well, he’s not gonna react well to it.

Gatiss: It’s poisoned! She knows! She’s onto him!

Moffat: “I’ve seen that gun. Damned if I’m giving him good tea!”