Mass shootings have been becoming more common in America, with one happening nearly every week. But have you considered what to do if you're in a dangerous situation with someone opening fire and attacking you?

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The U.S. Department of Homeland Security released a video recommending "run, hide, fight" for active shooter situations.

WPXI sat down with security expert Terrence Brown, who trains people and companies on how to handle emergencies.

"So, running's fine, but the issue with running ... is that you need to know where you're running to," said Brown.

Brown is retired from the U.S. military and is a former Pittsburgh police officer. He said a lot of people instinctively "fight, flight and freeze" in a crisis, which is understandable, but not good.

"You're fighting yourself. You're in disbelief that this is actually happening," said Brown.

Brown said it's important to be prepared and have a plan. That means before running, you should identify a safe place to shelter. David Johnson and Brown walked through WPXI, with Brown identifying what to look for: rooms and doors with no glass, and rooms that open to the inside, so they can be barricaded against an intruder.

When it comes to going to large outdoor events, it's just as important to be prepared.

"Get to know the areas, get to know the buildings that will be open late," said Brown. "To my right, I see a parking garage ... multiple levels, so that's wonderful."

Good places to run and hide are thick and solid, and don't have glass. That provides you safety from someone firing a gun at ground level or from up above. And when you're at an event where everyone is focused on one thing, like a performer, force yourself to look away and scan the crowd every once in a while.

Brown said it's all about awareness, whether in your workplace, in any other building or outdoors, especially where there are large crowds.

As for the last recommendation, fight, that's for when all else fails. In that case, you're trying to save your life, and the lives of others, in any way you can.