if he was timid enough to be cowed/dragged into it, I'd think that having a Dragonborn beat the living daylights out of your cult-leader with the aid of magic would be enough to scare him straight
what would be funnier though is Jherala's Warlock side coming out..."Oh, no, no. That's no way to get anywhere, trying to summon demons." as she remodels their summoning circle into a sprite-summoner instead
@daze413 yeah -- nobody thinks about arc flash damage from lightning-based weapoons