Retired Marine Cpl. Kyle Carpenter thought he was dead. He thought the enemy grenade had killed him. But he was still breathing. <br /> <br />“My body was torn apart by an enemy hand grenade … upon arriving at Camp Bastion, I was labelled P.E.A. — patient expired on arrival. I flat-lined at Walter Reed,” Carpenter says, narrating the short video. “The enemy killed me. I came back.”