Hmm... He said he dropped the sword because he was afraid he'd use it on you, so I think that may have been on purpose, to a degree?

The working theory right now is that it happens when his back is pressed up to a wall or the ground, or when a fight gets serious enough to activate his survival instincts. He doesn't remember anything during that time.

It does seem like the way to snap him out of it is to either knock him out or put him to sleep, so... well done on that front.

What was he like when he was berserking?