U.S. Air Force Master Sgt. Preston Davis, leased vehicle fleet manager assigned to the 379th Expeditionary Logistics Readiness Squadron, plays the part of a simulated casualty during an active shooter exercise conducted at Al Udeid Air Base, Qatar, Aug. 31, 2017. The active shooter exercise tested the knowledge and capabilities of emergency responders and service members across the base. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)