Senior Airman Thomas Cruise, 82nd Security Forces Squadron patrolman, provides overwatch as his partner clears the room during an active-shooter drill at the elementary school on Sheppard Air Force Base, Texas, April 20, 2018. During a sweep, the Security Forces member's jobs were to search for and neutralize the target. They are trained to move toward the sound of gunfire, but if they do not hear anything, they will search each room for the suspect. (U.S. Air Force photo by Airman 1st Class Pedro Tenorio)