I'm confused about the part with the teacher. Where I went to school ALL the teachers arrived 15-60 minutes earlier and went into their dedicated room. I don't remember exactly, but one of them coming in late was a "once every few years" thing.

Sure it sucks if you're early but I suppose they could also just get some take-home work (like grading tests) that's not due that day or prepare some stuff. Sure, some of them probably killed the time with morning newspaper and coffee... but still.