During an emergency, the key principles to follow are to Evaluate and Respond. These are the two principles we use at the University level when dealing with crises, and they are the same ones you should use as a department or individual.
Examine the situation to determine what the risks are. Is there a threat to your personal safety or the safety of others? Is critical patient care or research at risk? Are there plans in place to address these risks? Will these plans work? What are the different actions that can be taken?
Once you have evaluated the situation and understand your options, you are able to choose how to respond to the emergency in the way that maximizes your safety and the safety of others. Stay calm and use common sense.