In this video, U.S. Army Ranger SFC Petry remembers saving his fellow Rangers while clearing a courtyard in Afghanistan in 2008. Already shot in both legs while assaulting in, Petry noticed a live enemy grenade. He picked up the grenade and threw it. As a result, he lost his right hand.
He applied a tourniquet and remained in the fight until the area was secured. Once the enemy was neutralized, the wounded Ranger was moved to the casualty collection point, at which time he realized just how injured he was. You can read the official Medal of Honor citation here.
Video courtesy of USASOC PAO