Running. the social hall plunging into darkness. >> you have 30 seconds to save your life. move. >> what are these innocent victims of an approaching gunman in the hallway about to do? what do they need to do? just a few minutes earlier, these members of dallas's you w jewish told them not to freeze. >> you've got to fight for your life. you have literally no other choice. >> reporter: this is active training. the trainers are from the military, the fbi, the police, all part of the security community network, a non-profit group. >> the act of hiding prone and playing dead is the last act of a ...