Considering the enemies can all be revived (IIRC), them committing suicide one after another is not such a big deal. They are pretty weak anyway, and are not really the focus of this encounter, IMO.
As for being able to quaff potions while being in cow form, this is just everyday occurrence by Divinity standards. We've all seen way more ridiculous things.
So while this encounter is pretty bizarre, you'll have to be more specific about what you'd like to be fixed, exactly.
