Having picked Destroying Orpheus when talking to Orpheus at the end of The Lover, you chose the 'happy' ending to the tale. Kill Orpheus to receive an xp reward that makes taking the moral high ground worth it, then talk to Mary Ann - she thinks you should all leave now.
Thank you for sparing our lives. Can you take us to the surface now?
Head out of the dungeon, watching out for the zombies that have respawned.
Talk to Logamir as soon as you get outside the dungeon, otherwise he'll wander off. If you do lose track of him, check around the High Elf Outpost 2. Talking to Logamir will give you your reward and end the quest.
Look! I am alive again! How can I possibly thank you?
- Bug? After you kill Orpheus the tasks to complete the quest, and the logbook dialogue, seem to appear under 'The Lover' rather than 'Changing Sides'