My lab is in one of the second story beginner labs, nothing that could cause any major damage - the strong acids locked up all that good stuff - as we're just starting to learn how to do everything.
We were working on a three part graphing lab today (oh my aching back from standing and bending over that damn counter) when there was an explosion from somewhere in the building, the power went out briefly, the alarms all came on - and everyone just kept working like nothing out of the ordinary had happened. Dr. Edwards - my prof from last term - stopped in to check and make sure everyone was okay and not panicked.
I have no idea what actually happened. But I do know there's a gas lab where they play around with some pretty volitle stuff. My kid brother was in chemistry club (making fireworks) and told me they blow up this lab at least once a term. If not more. I have a hunch that's what happened. And he had warned me. If there's an explosion in the building, don't worry unless the teachers start looking scared. Very, very strange. *Grin*