Staff Sgt. Malcom Mullen, 921st Contingency Response Squadron security forces, responds to a simulated gunfire attack at the Geronimo Landing Zone during a mission in support of Green Flag Little Rock exercise, Feb. 11, 2019, Fort Polk, La. The primary objective of the exercise is to support the Joint Readiness Training Center and provide the maximum number of airlift crews, mission planners and ground support elements to a simulated combat environment with emphasis on joint force integration. (U.S. Air Force photo by Tech. Sgt. Liliana Moreno)