It looks as though you can't talk about what to do if something similar happens in your classroom.
For all the protestations about not restricting academic free speech, there certainly seem to be some areas that are strictly off limits. It is interesting to see what comes up that way. I would not have thought personal safety would have been one of them.
It is best to think about the unthinkable before the unthinkable starts happening. The thing of it is that bad things happen and ignoring them won't keep them from happening.
You can decide now if you will stay away from drugs, alcohol and how you might react to a terrorist attack. The Boy Scout Motto is "Be Prepared" I am an Eagle Scout, and what I learned most about being prepared is, it is more about mindset then equipment. Not that equipment isn't useful but knowing what to do in a situation helps you overcome the "freeze" when your mind is trying to figure out what to do and you've not thought about it before.
Virtually all training is centered around the idea of "when this happens, do this." This radically decreases the amount of time that you will take to react to a situation. Typical reaction times are around 0.2 sec. While a person will decide on a whether a website is good or not is about 3 seconds. So you can save quite a bit of time if you do the decision making process first, not in the moment, which takes a long time.