The joke has Lambert rolling his eyes, even as he smirks.

"Did you know all of that before or after you decided to take up being stage manager? 'Cause that seems like it probably would've influenced that decision."

Or maybe it wouldn't have. Whatever Joker wanted, he supposes, he could have arranged just working as an ordinary employee under a contract so he didn't need to take it on if that had been his goal in the first place.