In the course of an average 11 PM  to 7 AM shift, a person can only do so many things to keep himself occupied before there's nothing left but the L.A. Times crossword puzzle.  He can make the schedule, which he has done (Poppy can't work Tuesdays anymore because she has a night class, he's actually going to have to fire Drew because even the most apathetic of managers can only ignore the coke residue in the employee bathroom so many times), he can restock the cigarette cartons, he can clean every single mirrored surface in the store until the reflection of his ridiculous eyes is inescapable, he can even occasionally wait on a customer.  Mostly he is refusing cigarettes to minors, whose stray thoughts produce a variety of expressions he doesn't bother to control.

Frequently, this makes them go away faster, and Liam is all right with this.  At 3:09 AM "Ziegfeld Follies hit song of 1913" (eleven letters across) is eluding him, and in the strange way where he never really feels much of anything, he is content. 

From experience, he should know this indicates a massive upheaval of some kind shortly incoming.