Finding a movable tripod platform used for gunnery training, Finn attached the .50 caliber machine gun and pushed the platform into an open area, from which he had a clear view of the attacking aircraft. He fired on the Japanese planes for the next two hours, even after being seriously wounded, until the attack had ended. In total, he received 21 distinct wounds, including a bullet through his right foot and an injury to his left shoulder, which caused him to lose feeling in his left arm.