A Navy corpsman with Combat Logistics Battalion 31, 31st Marine Expeditionary Unit, treats a simulated casualty during a mass casualty drill Jan. 21, 2016, on Camp Hansen, Okinawa, Japan. The mass casualty drill was part of a noncombatant evacuation operation training evolution conducted during the 31st MEU’s Marine Expeditionary Unit Exercise II. (U.S. Marine Corps Photo by Cpl. Thor J. Larson/Released)