Go back to the main hall.

You walk all the way back to the main hall for no apparent reason other than sheer boredom. It's just the way you had left it, except with absolutely no one in it. Well, you aren't exactly a fan of crowds anyway.

Your eyes catch the nearby clock as it tells you that lunch break is almost over. Maybe it would be a good idea to get out of here before everyone outside decides to get back in so they can get to class. You'd hate to be stuck in a crowd of anxious teenagers, pushing and shoving each other.

Obviously there's nothing to do at the library, as you recall. So it's either to the locker room, cafeteria or to class. Unless you can figure out somewhere else to go to...