SAN ANTONIO -

Most people typically think of schools, public malls or theatres, and their workplaces as safe environments, but as seen in the recent mass shootings across the country, that may not always be the case. 

Doug Dempsey, with the Tactical Safety Institute in San Antonio, teaches a class on what to do should an active shooter ever enter a building or facility, where you are.

“It can happen, unfortunately, as we see in the news so often -- any time, any place,” Dempsey said.  “Either you can run, you can hide, or, if your life depends on it, you can fight.”

According to the Federal Bureau of Investigation, 51 percent of all active shooter attacks happen in the workplace, 17 percent happen in schools, 17 percent in public places, and 6 percent in religious establishments. READ: Active Shooter Statistics

Dempsey, who uses the Department of Homeland Security’s “Run. Hide. Fight.” video to train his students, said the choice you make, depends on one’s situation. WATCH: "Run. Hide. Fight."

“If you're in the area that the gunman is, you can see him, he can see you, then obviously, you want to run,” Dempsey said.

If you can’t run, or don’t know where the shooter is, Dempsey said, it’s best to opt for the second choice, which is to hide.

“Lock your door, barricade it, turn out the lights, hide, and call 911,” Dempsey said.

Finally, if you’re left with no other choice, Dempsey said grab what you can to use as a weapon, and put up a fight.

“The reality is, this can happen,” Dempsey said.  “So rather than be fearful and unsure of what to do, I'd rather get some training and know how to react and what to do.”