When I had the "zombie" Minthara in MR towers prison, the only way out I found was to go back to a save before entering. (I'm not sure anymore, but there could have been an autosave when you went downstairs... This was on the default difficulty) Anyway, after going back to the prison, I immediately attacked the guards and then let Minthara come with me to escape. NOT let her wait until I come back. I 've done this several times since then, also on tactician, and never had the problem anymore using this sequence. I always had the impression that the "inertness" was due to Minthara being in some kind of dialogue mode that didn't end.
I'll have to try having Gale giver her a smack with his puny arms next time this happens, the stuck in dialogue idea you're suggesting sounds very logical.
