Senior Airman Deanna Sena, 51st Medical Operations Squadron immunizations technician, removes her M-50 gas mask during readiness exercise Beverly Herd 16-01, May 9, 2016, at Osan Air Base, Republic of Korea. Medical personal treated patients with simulated injuries during the exercise while simultaneously ensuring they utilized the proper Mission Oriented Protective Posture gear. (U.S. Air Force photo by Senior Airman Victor J. Caputo/Released)