LPT: You can walk through the emergency exit of most buildings (without triggering the alarm) if you use the second door.

Generally the emergency exits of schools/universities/libraries etc have TWO sets of doors. The first door doesn't trigger the alarm, and when you close it, you must open the next door in less than 3 seconds or the alarm will trigger.<br><br>Of course this shouldn't be used to skip school... Or to sneak food into a library for example.<br><br>EDIT: I didn't know it was so common lol.