Lopez engaged the enemy immediately after landing with the assault waves. He exposed himself to enemy fire in an attempt to throw a hand grenade into a pillbox whose fire was pinning down that sector of the beach. He was wounded by enemy gun fire and dropped the grenade. Unable to grasp the hand grenade firmly enough to hurl it, he chose to sacrifice himself rather than endanger the lives of his men. He cradled the grenade under him and absorbed the full impact of the explosion, thus saving the lives of his comrades. Lopez was nominated for the Medal of Honor. Lopez however, was not the only Hispanic member of the 5th Marines, 1st Marine Division to be awarded the Medal of Honor. PFC Eugene Arnold Obregon (1930–1950), who also participated in the Inchon landing, was posthumously awarded the Medal of Honor for his actions 11 days after Lopez gave his life. Obregon was killed in action while using his body to shield a wounded fellow Marine.