During an important military exercise, another Air Force member and I were working in a radar van under a simulated attack. We were under strict orders not to open the door unless we received the secret code, which we had been given at the morning briefing. Later in the day, we heard knocking at the door. Remembering our orders, I yelled out “Fort” and waited for the correct response, “Knox.” It never came. Several minutes later we heard more knocking, but again we didn’t receive the proper response.

Over the course of the afternoon, various others came to the door and knocked, but no one gave us the correct password. Proud of ourselves for not being tricked into opening up to the enemy, we later received a phone call from a furious superior officer who told us to open the door immediately. After we explained that we were simply following orders, he informed us that the code was not “Fort Knox,” but four knocks.

Contributed by Ssgt. Lynda C. Lovell, Reader’s Digest, July 1997, p. 139