Emergency responders pose this scenario: you're deep in work at your desk, when suddenly the sound of gunfire and screaming wash over you. Somebody is repeatedly firing a gun in your office and your co-workers are hurt or, perhaps, dead.
What do you do?
This situation won't happen to most people. But in case it does, the city of Houston prepared a very realistic six minute video instructing people what to do should a gunman open fire in a public place. There are three basic responses: run, hide and fight.
Running is the best choice - get out of the building or area quickly and don't let anybody slow you down. When you're safe, call 9-1-1. If you can't get out, hide. Turn off room lights and silence your cell phone to evade the shooter's attention. If you must face the shooter, do it decisively. Use improvised weapons (like a chair or a fire extinguisher) and fight aggressively.
Remember, when the first police officers arrive, they're likely coming in heavily armed and with a purpose: they're there to stop the shooter, not to treat the wounded. Emergency medical teams will follow.