So how do you increase your chances of surviving an active shooter situation? You need to know the ABC's: avoid, barricade, and confront.
David Katz, with Global Security Group, uses scenarios like an active shooter situation about to take place in an airport this to train police officers. But it also illustrates how most innocent people will react.
"The last thing you want to do is freeze," said Katz.
But one innocent couple does not move. "Point in face, most people in the same situation won't move," said Katz.
That's when David says you need to remember your ABC's. The first being, avoid.
"If you have a clear path and if you can, run and get out, do it," he said.
If you cannot get out, think 'barricade' for your next line of protection.
"Get into a room like this one, close the door, lock it if possible and put whatever piece of furniture you have in that room against the door, you want to pile it up," David said.
And if you are in a larger group of people, your next option is to 'confront' the shooter.
"You throw whatever you can," said Katz. "You pick up objects, a fire extinguisher, use that. Distract them. And worst comes to worst, you use your hands and attack them in a very, very delibate manner and do not stop until they are no longer a threat."
A Homeland Security video on YouTube, that explains how to save yourself, has gotten more than 3 million views.
Click the image for the full report from Monica Malpass on how you can save yourself and others.