My high school chemistry class missed an authentic fire evacuation. The teacher, a truly brilliant woman named Ruth Mazuski, was preparing a demonstration involving solid phosphorous which explodes when exposed to air. The glass jar containing phosphorous slipped from her hand and landed in the sink. Talk about fireworks. Most of the class thought it was part of the demonstration. My lab partner, Lynn, and I sat right in front of the sink, though, and we saw her face as the jar fell. We dived under our table and waited it out. The pandemonium in the room was such we didn't notice the fire alarm set off by the smoke in the classroom. By the time the fire department came roaring into the room, the alarm was off, the problem was contained, we were all sitting peacefully in our seats looking at the fire fighters with mystified expressions and innocently asking, "What's going on?" It was the best class I ever had.