U.S. Air Force Tech. Sgt. Jarad Underwood, 22nd Training Squadron Advanced Skills Training NCO in charge, and Staff Sgt. Corray Valentine, 22nd TRS AST instructor, demonstrate a “shield block” during a combat survival training for aircrew and battlefield Airmen at Fairchild Air Force Base, Washington, Jan. 31, 2019. Underwood is the first and only person in the Department of Defense who is eligible to teach combatives to members in all military branches. (U.S. Air Force photo/Senior Airman Jesenia Landaverde)