From Oak Park to Pittsburgh, we all realize that these days a mass shooting can happen anywhere, at anytime.
If a shooter walked into your workplace, whether an office building, a school, or a movie theater, would you know how to survive?
They're words we've heard too many times: "We have an active shooter. Stand by for further information."
Jim Hardman is a Desert Storm US Army veteran and former police officer who teaches survival classes at Premier Shooting and Training in West Chester, Ohio.
In an active shooting, he says everyone should know three key words: run hide, or fight.
Hardman says wherever you are, always know where the exit is.
"I walk into a store or a new business," he said, "and ask myself where can I get out?"
Hear gunshots? Hardman says run if you can, without running into gunfire.
"If I decide to run, I move with a purpose," he said. "I'm not just running though the center or a room to try to get away."
Hardman says look for a spot that might stop bullets.
"I position myself to where I''ve got that filing cabinet, that copier, something that's heavy."
Hardman says never try to reason with someone already shooting. Statistics show you cannot stop him at that point.
"Once that active killing starts, that rationalization is out the door."
Obviously your best bet is to escape. But if you can't get out, Hardman says the next thing to do is to start barricading the room you're in, putting heavy everything at the door to keep the shooter out.
"I might just grab an entire desk assembly, slide it over in front of the door, " he said.
And he says then look for a way to secure the door with a rope or strap.
Once the door's barricaded, Hardman says turn off your cell phone's ringer, as it will give you away, and make the room dark, but closing shades and lights.
The darkness gives you, not the killer, the element of surprise.
"I turn off the lights and that's what confronts him when he comes in that door," he said.
If the shooter comes in, Hardman says blind him with a flashlight -- even your phone's light -- which gives you a chance to knock down his weapon, as he demonstrated to our camera.
Hardman says if you don't try to reason with a shooter, never run into the path of bullets, and don't hide under a brightly lit desk.... you've just increased your chance of survival.