Dave - My answer to your question would be for you (or anyone) to first sit down and complete an analysis of exactly what the most likely hazards to you are. I don't think an event such as that which occured in Blacksburg Monday will fit into the "most likely" category, do you? That was an aboration, tragic though it was/is.

Once your analysis is complete, decide what risks these hazards present to you and others while in the classroom. Most hazards will present no risk in the classroom environment, but may present risks going to and from class, i.e., lightening, temp. extremes, etc.

Next, decide what mitigation efforts that are reasonable for you to take in order to eliminate or lessen the risk(s), such as keeping certain gear available and conveniant for your use when conditions warrant.

Finally, for those abhorant situations, practise using good "situational awareness". Learn where trouble is most likely to occur and avoid those areas. Watch for tell tail clues that conditions may be deteriorating and take appropriate action to distance yourself from possible harm. Be observant and aware of what's going on around you, and try to recognize escape routes in case they be needed.

These are simple things, but of high value, that anyone can do. They can employ it everyday in all environments, not only a classroom without going to the next level of personal protection that might require physical interventions up to and including deadly force.