Dion Harris, 28th Security Forces Squadron lead instructor (left), evaluates Staff Sgt. Tylor Evans, 28th SFS response force leader, as he troubleshoots a malfunction in his M4 rifle during a training session at Ellsworth Air Force Base, S.D., March 10, 2015. During the training, Airmen were evaluated on how they dealt with weapon malfunctions under stress. (U.S. Air Force photo by Airman 1st Class Rebecca Imwalle/Released)