I don’t think Brann is ignorant: Going by the fact he blatantly keeps gold for himself and gives his companion a pittance, I think he knows exactly what he’s doing when he throws his potions in nuclear waste.
Xal’atath isn’t the real threat, here.
Anyway, the Visions NPC is going to be entirely optional, so you can do it solo like it used to be. It’s nice for players to have the option though, including healers who may not be able to do a run otherwise.