 During an enemy attack on August 7, in an assembly area of the North Vietnamese Army in the A Shau Valley of the Republic of Vietnam, Hagen led his small recon team's defense, and when USASF Sgt.Bruce Allen Berg was hit by a rocket in one of the team's bunkers, Hagen crawled towards Berg's position through heavy fire in an attempt to assist Berg, returning fire as he proceeded.Mortally wounded in the process, Hagen was later posthumously awarded the Medal of Honor for his actions.