[Gatofeo]

We had something similar when I was a Security Policeman in the Air Force in the 1970s -- and an unofficial one as well: "Never forget that the badge you're wearing is always one rank higher than the person challenging you verbally or physically, as long as you're right and he's wrong."
Our sergeants, many of them Vietnam veterans, taught us that one.
And yes, plenty of Airmen were in combat in Vietnam. I worked with many. One Tech. Sgt. I served under had a Silver Star for manning his machine gun at an airbase that got overrun. His bunker took a direct hit from a rocket, and he was the only survivor.
He never mentioned it; the other sergeants told us his story.
We had many fine sergeants in the years right after the Vietnam War, when I served. They'd "seen the elephant" and knew how quickly and terribly a situation can become lethal.