First stop, trapped room. The fake Karavakos seemed too cowardly to be legit, and it turned out he wasn’t. A few seconds after most of the party entered the room, two candle holders started spewing poison gas (Alissa wisely decided to stay out of the room). It wasn’t very threatening, mostly (thanks to Jett’s damage reduction spell), and the heroes eventually shut down the gas traps to the point that Jett’s spell kept them from getting hurt. Meanwhile, outside in the hallway, Alissa figured out a weak spot in the wall of force, and showed Loodra where to hit it by illuminating it with magic missiles.
After a short rest, they pushed on to the next room, which was much more challenging, particularly without Jett’s damage reduction spell. The lost souls in the walls kept a constant barrage of psychic energy pouring into everyone’s brains. More of the 4 armed skeletal guards did a lot of damage quickly (with their 4 scimitars), and then the Banshees started screaming through the walls. It was a close battle, with most of the heroes close to death at several points in the fight and Jett out of healing spells early in the battle (used to keep Loodra and Hogar conscious). Wynne ended up having to leave the room and consume healing potions, and Jett even used a powerful healing potion on Hogar as well.
In the end, the heroes won, but everyone had to run for their lives to make it out of the room before the psychic barrage finished them off.
During the battle, Alissa discovered double doors on the far side of the room, but wisely chose to ignore them and concentrate on the banshees.