This is a statement about the MC. His issues come from the fact that everyone else (the external world) sees him as only Birdman.
Correct. But Situtations aren’t just about physicality. The son of a king is in a situation, the class clown is in a situation–if his problems come from his status as the class clown. If they come from difficulties setting up his pranks, then he could be in Activity – which is why it’s important to go broader than just a brief description.
He is annoyed during the interview early in the movie because one interview is a cheap hollywood interview, and the Korean is only interested in him because “You were in Birdman 4?”
So, it’s a Situation. His motivation to put on the play is this, his purpose is to break free of his reputation with a successful play, but the IC is tempting him to change his attitude, accept it, and become a a Be-er.