U.S. Army Sgt. 1st Class Casey Kiernan, a senior medical Observer, coach, trainer; assigned to the Joint Readiness Training Center, instructs Pvt. Patipan Matchawate, mechanic, Golf Company, 2nd Battalion, 319th Airborne Field Artillery Regiment, Fort Bragg, N.C., in safety during a field exercise at JRTC, Fort Polk, La., Oct. 18, 2012. JRTC 13-01 is designed to prepare and educate U.S. military service members in a simulated combat environment.