from Wikipedia: On September 29, 2006, Monsoor’s platoon engaged four insurgents in a firefight, killing one and injuring another. Anticipating further attacks, Monsoor, three SEAL snipers and three Iraqi Army soldiers took up a rooftop position. Civilians aiding the insurgents blocked off the streets, and a nearby mosque broadcast a message for people to fight against the Americans and the Iraqi soldiers. Monsoor was protecting other SEALs, two of whom were 15 feet away from him. Monsoor’s position made him the only SEAL on the rooftop with quick access to an escape route.

A grenade was thrown onto the rooftop by an insurgent on the street below. The grenade hit Monsoor in the chest and fell onto the floor. Immediately, Monsoor yelled “Grenade!” and jumped onto the grenade, covering it with his body. The grenade exploded seconds later and Monsoor’s body absorbed most of the force of the blast. Monsoor was severely wounded and although evacuated immediately, he died 30 minutes later. Two other SEALs next to him at the time were injured by the explosion but survived.