Even after he was seriously wounded , Lt. Col. O'Brien refused to be evacuated .
After Lt. Col. 's 's pistol ammunition was exhausted Lt. Col. O'Brien manned a . 50 caliber machine gun , mounted on a jeep , and continued firing .
Even after he was seriously wounded , Lt. Col. O'Brien refused to be evacuated and after his pistol ammunition was exhausted , he manned a . 50 caliber machine gun , mounted on a jeep , and continued firing .