If you need a reason to not sleep through class, this thread of serious lab accident stories gives you a pretty decent one.

Note that most of these were chemical incidents perpetrated by biologists and engineers.

How many of your other classes can potentially prevent you from dying a horrific death in the lab?

Here are more stories.  There’s also a video, further down the page, that shows barrels of sodium being dumped into a lake.

I’m thankful to have avoided lab injury, except for one lightly-THF-contaminated needle stick and a few small lab fires.