this happened at my hS too and i was in gym class at the time and it was winter. THAT bites...
oh man, in my skool we had a bomb scare and got to leave early...it was spring time! so nice! and then in the science lab acid had spilled over night and we got delayed openings for that... so sweet no science :-D
my school had quite a few bomb scares---one time when i was teaching spanish at the daycare we had to each take or carry 5 kids to get them as far away from the building as possible.