Maybe it's Only a Partial Gate to Hell
We have the Chelish Crux and are out of the Asmodean Knot. I suppose we should take the Crux to the pathfinder who asked us to retrieve it. Or we could open it first, just in case. We don't know what will happen and it may be best to be prepared.
'If we open this and it creates a gate to hell...' says Ganelon, always thinking the worst.
'...then mission accomplished. It will be like every other adventure we've been on.'
'Plus we'll have opened the gate not where the pathfinder wanted it', says Skelra, pointing out another good reason to try.
'Oh. Right. I suppose I'd have a gate to hell in my bedroom. I suppose it would keep me warm in Winter, and act as a nightlight.' And so, unperturbed by the paladin's familiar overreaction, Skelra and Afutavere get to work trying to open the Chelish Crux, working by trial and error. Lots of error.
Each failure in opening the Crux brings some pain. Some of the faces of the Crux glow red and a burst of heat flashes out, scorching the holder. And despite being a wizard and supposedly intelligent Skelra manages to be pretty slow in determining the locking mechanism. He gets scorched, scorched, and scorched again, soaking up damage with healing potions and stealing hit points from the elf.
Eventually, enough luck gets the Chelish Crux's combination correct, and it starts to unfold. Skelra immediately sees what's inside the Crux: an Erinyes devil's severed head. An Erinyes devil's severed head that starts screaming its lungs out.
'What lungs? It's a severed head.'
'I was being figurative, shut up.' So the severed head is screaming at an almighty volume in the infernal language as soon as the Chelish Crux is opened.
'With all this commotion, I think our monk's going to have to move house.'
'Uh, this is hardly the first time a woman has been screaming in infernal in my bedroom. I'm just saying.'