Airman 1st Class Robert Siegmann, 99th Security Forces Squadron, subdues and handcuffs a simulated active shooter during a base wide exercise at Nellis Air Force Base, Nev., May 12, 2016. These real world scenarios combined make this exercise one of the largest in the history of Nellis AFB. (U.S. Air Force photo by Airman 1st Class Kevin Tanenbaum)