These annoy me. Your life bar must be below 500 or worse yet 250 health, so chances are you'll need little to no vitality since any enemy that can take you down to health or less health easily is someone you don't want to fight with so little health. I'd recommend on easy do the massacre yakuza mission, they hit for very little damage, so wait til they get you done to less then the 500/250 you need and use the base move.