A Marine escorts an ambulatory HMMWV to a Shock Trauma Platoon during Exercise Steel Night’s mass casualty drill at Marine Corps Air Ground Combat Center Twentynine Palms, Calif., Dec. 12, 2015. The drill tested the 1st Marine Division’s ability to react to a large influx of injuries and wounds from battling the enemy. Steel Knight provides tough, realistic training for the Marines and sailors of 1st Marine Division. - A Marine escorts an ambulatory HMMWV to a Shock Trauma Platoon during Exercise Steel Night’s mass casualty drill at Marine Corps Air Ground Combat Center Twentynine Palms, Calif., Dec. 12, 2015. The drill tested the 1st Marine Division’s ability to react to a large influx of injuries and wounds from battling the enemy. Steel Knight provides tough, realistic training for the Marines and sailors of 1st Marine Division.