A U.S. Air Force member with the 18th Security Forces Squadron and the perpetrator of a simulated active shooter exercise lies on the ground after a brief simulated fire fight with emergency responders, at Kadena Air Base, Japan, during an active shooter scenario May 4, 2016. For this exercise, security forces responders and the active shooter were authorized to use simulated ammunition for the first time in order to better prepare the responders for potential real-world scenarios. (U.S. Air Force photo by Staff Sgt. Maeson L. Elleman/Released)