Sadly NPCs are not very smart when death fog is involved. Running straight into death fog is standard stuff for them.
The remark "That sounds like the queen" is triggered when you're a few steps past the illusory wall. About 2 more steps and she will break down the door. You can trigger this during the fight and she will join the fight with you. Otherwise, if this happens when the fight is already over, she will just initiate dialog immediately.
