Pena is being recognized for his actions on the evening of Sept. 4, 1950, near Waegwan, Korea, when his unit was fiercely attacked. During the course of the counter-attack, Pena realized that their ammunition was running out, and ordered his unit to retreat. Pena then manned a machine-gun to cover their withdrawal. He single-handedly held back the enemy until morning when his position was overrun, and he was killed.