There's indeed two path for Irinlia now, the 'bad' one requiring to send her to your dungeon, the 'good' one to give her to the guards (and then visit her to the prison and freeing her).
For the tentacles scene, you must have chosen the 'bad' path for Irinlia as well as Lace, and have cleared the hard (or advanced, I'm not sure) level of the Spire of Courage in Begus. Then, talk to the guard at the bottom floor of your dungeon, he will give you the quest to take some spore and grow the tentacles. Then I think you must talk to Lace to trigger the scene.