Maj. Heidi Shelstad, 823rd Base Defense Squadron (BDS) physician assistant, teaches the 824th BDS Bravo Flight how to conduct advanced combat casualty care (AC3) at Moody Air Force Base, Ga., May 5, 2020. AC3 is necessary training for the 824th BDS before it begins its cycle on the Immediate Response Force. (U.S. Air Force photo by 1st Lt. Faith Brodkorb)