Yes, yes, she's getting the sense that wandering around Dispater is stunningly lethal if you don't have a ninth circle cleric defending you, presumably smarter Carissa knew that when she came up with this plan.
They're attracting a bit of an audience; not much overt, but lots of devils trending in their direction substantially more than chance, some of them invisible about it, some of them disappearing by Teleport from behind them only to appear by Teleport ahead of them.
The stairs are only a few minutes, thankfully, and then they're winding through a hallway decorated on both sides with a spectacular green-glowing forest of construct trees made with eerily mathematical precision, each one precisely alike, some gooey bloodlike substance pulsing through their false-veins in perfect synchronization. It's quite cold. She already had Endure Elements up.
They pass by a ballroom, where dancers move gracefully in perfect synchronization, their smiles gentle, their eyes desperate and pleading. They pass by balconies overlooking an utterly silent library.
And then Dispater's waiting-room, a mockery of a comfortable warm parlor such as you might find in many places outside Cheliax, with stuffed armchairs to suit all body-configurations and drinks and snacks set out and an ordinary fire in an ordinary fireplace. And a silken rug that's got some powerful enchantment laid about it spread across the whole floor.
Carissa stops short of it; Dispater can do whatever He wants to her, obviously, but she's not sure she's supposed to just walk into it.