I don't understand the last two posts, but since this hasn't been bumped from too long ago....
Discerning defense from vengeful judgement is a simple matter.
Disgruntled people usually only transition from posturing ---> serious violence when they feel there is no hope, so convince them otherwise.
As someone who's had food, plates, and pans thrown at them...been threatened, punched, and seen the pointy end of a knife waved in a disconcerting way, I recommend that a cook acting erratically use the transition to a new job to regain their self respect, and be forced to cut back on the drinking. Rarely, if ever, have I seen a guy get out of control and worry for myself or the restaurant. Lets be honest the money lost from a lazy/sloppy cook will almost always be more than losses from one theft or fight.
A few years ago, one cook came in to eat ... maybe 10 drinks into his night, got cut off, got angry, and started swinging...he was fired. When I ran into him a few weeks later, I reminded him that I'd gladly put up with his attitude, his disdain for managers, his consistent 15 minutes late, and crazy loud singing in the kitchen and still always want to steal him from another restaurant, because he was a beast on line... but knowing his wife and boys I couldn't have him on as a drinker ... and in a smaller town he knew I told the same thing to a dozen other restaurants. Today we're both a little older, get home a little less drunk, and get paid more.
Setting aside the rare, saddening, serious mental conditions, most outbursts will be isolated to some sort of trauma eg. divorce, or the mark of someone too old to be drinking that heavy. I'm sure there are lots of other explanations, and not to sound like a HR douche, but first try to identify the issue, show some level of validation, and present the dismissal as a positive change. Because frankly, most guys in the industry know the salary cap for line cooks are low enough that parity isn't going to be perfect, but its manageable.