Staff Sgt. Tanya Jimenez, 28th Security Forces Squadron response force member, and April Miller, 28th SFS police officer, sweep a room during active shooter training as part of the Defender’s Edge program at Ellsworth Air Force Base, S.D., July 23, 2014. Defender’s Edge is designed to provide realistic training to security forces members and mentally and physically prepare them for various situations they may encounter. (U.S. Air Force photo by Senior Airman Hailey R. Staker/Released)