then land to deliver a Shivering Touch on the enemy cleric.
If I were going the shivering touch route, I'd spring that little gem on them first. I suspect they will surrender without you doing anything else. I know I would.
Shivering Touch is an I win button after all.
Or, instead, maybe you could say "I got this one guys" before the evil party talks to any important NPC. I did that for a while in a game were my character was a changeling shapechange ranger/old style shifter prc. Played it up as I was their prisoner/hostage, and talked NPCs into more helpful positions. The dm liked it, the party hated it after they found out my guy could decimate the entire party(so much so the group wanted me to change characters). Never needed to use any of my powers except to change form to get around obstacles. "I'll find another way up this mountain, later guys. You have the keys to my cuffs right?" Evil party or even party on party can work if the dm runs arenas every few games. Gets the animosity out.