[If "dislike," "apathy," "idiocy," and "madness" all look the same to her... He pities her patients.

And as for listening... Well.]

Careful with your friend. [It's almost a genuine warning. ...Except he knows she won't listen, and that's her own fault. He's speaking to her back, but it will be said.] He won't bite the hand that feeds him-- he'll tear the throat out and devour you as you die.

[Melodramatic? Well, yes. But the Holmes men are. And he punctuates the last word by not slamming his door but snapping it shut.]