U.S. Air Force Master Sgt. Scott Wagonblott, 633rd Communications Squadron information assurance manager, scans a parking lot during an active-shooter exercise at Langley Air Force Base, Va., Nov. 19, 2013. During the exercise, Wagonblott and other Airmen simulated an emergency situation to test readiness of first-responders and organizations across the installation. (U.S. Air Force photo by Airman 1st Class Victoria H. Taylor/Released)