I recently two-maned ID (eNorm) on an arcane archer. From the initial confrontation by the door, my archer was unable to shake her aggro, preventing her from patrolling the hallways.
I just now did it on eNorm with a rogue stick fighter (legendary dreadnaught), and after the initial fight (where she demonstrates her ability to sacrifice for a power up), she would not leave the area, and actually came to the door to attack me. I beat her, and finished the adventure, but without ever leaving the foyer, or her sacrificing anyone for a power up. It seems like maybe the quest is bugged? Or have they changed it on one of the last couple updates?