Clayton Denney, 28th Security Forces Squadron security officer, apprehends Staff Sgt. Lance Bradshaw, 28th Communications Squadron voice networks NCO in charge, as part of an active shooter exercise at Ellsworth Air Force Base, S.D., Aug. 12, 2014. The purpose of the exercise was to test reaction and response time of the 28th Bomb Wing to an active shooter scenario. (U.S. Air Force photo by Senior Airman Zachary Hada/Released)