Has any ex-special forces soldier gone bonkers before?

One of the Rambo films (not sure which it is) portrays him as being hunted in a forest by the national guard, where he systematically blows up everyone and everything (in true Hollywood style). Has this ever occurred with any real ex-SAS, SEALS etc. soldier (i.e. the military has been called in to subdue the soldier, as it is too dangerous for a police team?) Could it ever happen? I’d imagine that the average SWAT team is pretty well trained, but for example, how would they square up with a single ex-SAS soldier?

Well, I imagine that if the ex-commando went really crazy—like “trying to eat his own fingers” crazy—he wouldn’t exactly really pose much of a danger than anyone else suffering from a severe mental illness would.

One of my Dad’s friends was with the Special Forces in Viet Nam. Two tours, decided the second chest wound was maybe a hint it was time to get out. He used a souvenir AK to chase a cat out of his back yard one time, but by all accounts that was something he’d have done before he signed up. I know, it’s not really an answer, but it’s a pretty cool story.