A simulated gunshot victim lays on the floor at the 633rd Civil Engineer Squadron building during an active shooter exercise at Joint Base Langley-Eustis, Va., Dec. 15, 2016. After the building was cleared by the 633rd Security Forces Squadron, first responders from other agencies arrived to treat the individuals with simulated injuries. (U.S. Air Force photo by Senior Airman Kimberly Nagle)