Captain Allen was the pilot of a B-26C with the 8th Bomber Squadron, 3rd Bomber Wing based at Kunsan Airfield (K-8), South Korea. On 1 July 1953, while on a night intruder mission near Cho-do Island, North Korea, his aircraft was hit by anti-aircraft fire and the crew bailed out. He was listed as Missing in Action and was presumed dead on 2 July 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

For his leadership and valor, Captain Allen was awarded the Silver Star Medal, the Distinguished Flying Cross, the Air Medal with 2 Oak Leaf Clusters, the Purple Heart, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.