So, I'm running the original 3e version of Forge of Fury, and my players are about to meet Idalla, the succubus. In the 3e version of the dungeon, Idalla is bound to the room, and just wants to leave. If she's attacked by a Good aligned character, she is free to leave... for some reason. Or, if she's granted permission from a Good aligned character, she's also free to leave.

I'm not at all sure how to run this. I foresee her explaining to the party that she's been magically bound to the room, and that the spell is broken just by giving permission, and then the party just... does. And she teleports away.

That seems totally pointless.

I really like the idea of there being a powerful being trapped in this room, though. It serves my purpose to have some sort of unexpected guardian in this space, and a filter that allows Good aligned characters through is really convenient in its own right.

Clearly, the solution is how I play the character, then, but I just cannot get myself inside her head. How do I make this interesting, and last longer than a single back-and-forth verbal exchange? The module gives her only real goal as being to leave, and I don't have a reasonable, interesting alternative.

Have you run this module before? How have you handled Idalla?