.. That sounds not fun for me and many people I know.
I don't want a boss pulling some "hidden" team wiping mechanic out of nowhere. AI's can nearly always "outplay" characters easily. Just Calculate exactly when something will do the most damage or cause the most havoc and do that. Random paralyzes that freeze you JUST when you don't want them to. The reason this isn't in the game is it would absolutely destroy the fun for likely thousands of players.