Unlike the Queens of the Palace of Whispers or the Palace of Mania, the Queen of the Palace of Rot is a legitimately evil person. Vissenta leads a cult of the undead, torturing and manipulating to her own ends. She plans to lay claim to several members of the Phandelvers, who themselves straddle the line of alive and not.
Nobody leaves the Anthroparions. Not as long as Vissenta has her way.