This is a classic road rage incident, except that it appears to have happened on or near a U.S. Military Base.
In the plus column, the fellow service men who came over and provided security until the MPs showed up were a welcome feature that would not be present in the civilian world.
In the minus column, this jarhead has presumably had access to loaded firearmsnice ones! Please tell me he's a State-side refrigeration tech servicing commissary walk-ins who has never been issued live ammo outside of boot camp.