Marines and sailors with 1st Battalion, 5th Marine Regiment, transport notionally-injured role-players to be medically evacuated by a CH-53E Super Stallion helicopter during a foreign humanitarian assistance exercise at Kiwanis Park, Yuma, Arizona, as part of Weapons and Tactics Instructor Course 2-15, April 17. (Charlies Santamaria/U.S. Marine Corps)

An explosive ordnance disposal technician undergoes the decontamination process after leak, seal, package and decontamination training April 21, 2015, at the gas chamber on Camp Hansen, Okinawa. (Janessa Pon/U.S. Marine Corps)

Marines with Company B, 2nd Reconnaissance Battalion prepare to unload a Combat Rubber Raiding Craft and helocast off CH-53E Super Stallion helicopter during a four-day certification exercise aboard Marine Corps Outlying Field Atlantic, N.C., April 23, 2015. (Fatmeh Saad/U.S. Marine Corps)

A Marine with Company B, 2nd Reconnaissance Battalion prepares to jump from a CH-53E Super Stallion helicopter at an altitude of 6,000 feet during a four-day certification exercise aboard Marine Corps Outlying Field Atlantic, N.C., April 23, 2015. (Fatmeh Saad/U.S. Marine Corps)

Maj. Stephen Piantanida, left, briefs the Assistant Commandant of the U.S. Marine Corps, Gen. John M. Paxton, Jr., on the weapons capabilities of the AH-1W, before a flight in support of the final exercise at Marine Corps Air Station Yuma, Ariz., 25 April 2015. (Tia Dufour/U.S. Marine Corps)

An F-35B Lightning II with Marine Fighter Attack Squadron 121, based out of Marine Corps Air Station Yuma, Ariz., performs a vertical landing as part of required flying field carrier landing practices at the station?s auxiliary landing field, on April 27, 2015. (Travis Gershaneck/U.S. Marine Corps)

Tree frogs climb on Lance Corporal Chris Printy?s head April 28, 2015, at Territory Wildlife Park, Berry Springs, Northern Territory, Australia. (Jose O. Nava/U.S. Marine Corps)

U.S. Marine infantrymen with 1st Battalion, 4th Marine Regiment, Marine Rotational Force ? Darwin, go on patrol during a live-fire exercise April 28, 2015, at Kangaroo Flats Training Area, Northern Territory, Australia. (Reba James/U.S. Marine Corps)

U.S. Marine infantrymen with 1st Battalion, 4th Marine Regiment, Marine Rotational Force ? Darwin, run to cover as targets are called out during a squad assault drill April 28, 2015, at Kangaroo Flats Training Area, Northern Territory, Australia. (Reba James/U.S. Marine Corps)