How to Survive an Active Shooter Situation

— -- No one ever expects to be in a mass shooting, but the Orlando massacre is a reminder that it can happen anywhere at any time.

John Matthews, a 30-year law enforcement veteran and author of "Mass Shootings: Six Steps to Survival," shared tips on what to do if it happens to you.

The first thing you want to do is exit.

“Get as far from the shooter as you possibly can,” he said on “Good Morning America” today. “You may not have to go out the entrance that you came in. Look for any way to get out. A side door, back door, a loading door, maybe go through the kitchen.

“We heard several witnesses say they got out and put distance between themselves and the shooter, and resist that urge to go back in. I know you want to help your friends, but you don’t want to be a victim.”

If you can’t exit, the next best thing to do is to find cover.

“Cover is anything that will protect you from bullets,” Matthews explained. “We heard a bartender say we grabbed 10 people and dove behind the bar. The bar actually deflects bullets and saved lives. Jump behind a coffee or a soda machine, anything that will stop or deflect those bullets.”

If you can’t exit, and you can’t find cover, the next best thing to do is to conceal yourself.

"Get behind a curtain, anything that will shield you from the shooter’s sight,” he said. “We heard some victims say they actually pulled bodies over themselves and concealed themselves from the shooter. If you can get out of that shooter’s line of sight, then your chances of surviving go up instantly.”

Matthews said that his research of more than 70 mass shootings shows you should not engage the shooter.

“No, only as a last resort should you engage the shooter,” he explained. “Almost all the time that an unarmed citizen engages a shooter, they end up being a victim.

“Only during the following circumstances [should you engage]: When you have three or more people, when the shooter is engaged in a non-shooting activity and you can attack them simultaneously, do you have any chance to survive.”