That is interesting. When my (much older) brother in law came back from the war in Vietnam he'd dive under the nearest car at loud noises. My sister in law's brother came back from Vietnam as a basket case, pretty much zoned out on Thorazine. My mother told me stories of relatives who came back from WWII who were the same way as my BIL. Nobody was afraid they'd "go off" and start killing people. And they didn't.