So, I managed to kill the guy and I did not leave combat. Only my figher was able to move around, my druid couldn't do anything, and the rest of the party wasn't standing up (I have the main option checked). Moreover, my figher couldn't move freely around the room, as if encountering some hidden blocks. Sadly, I didn't save...
As for steps...
Ate a lot of food, went in, used all figurines, started fighting, killed trash, 4 characters got maimed, druid was perma frozen due to frightened and my last survivor 1v1-ed the lich to death. Aaaaand, I didn't exit combat.
Save game from before the fight:
https://dl.dropboxusercontent.com/u/30743737/fb60aa50-ce45-4f0a-93be-14283655c4c2%20quicksave.savegame
Output log:
https://dl.dropboxusercontent.com/u/30743737/output_log.txt
Specs are in attached.
DxDiag.txt