[Sebastian probably had a good reason to visit the bar. Most likely, he did.
It's just that when he opens the door to the owner's drunken karaoke, suddenly he finds himself reconsidering whether that reason really was all that good. And whether he should just turn on his heel and walk right out.
While he's deciding that, he just remains standing in the doorway, staring in slight... it shouldn't even be incredulity, come this point.]