I've just killed the Beast of Khemeria, but the trapdoor won't open. The wizard is down here with me, but he just says he has to inform that other guy right away and just stands there. Maybe I'm missing another exit or switch. Or maybe the game is stuck in a bug. Should the wizard be doing something? I saved just before talking to the wizard (in the beast lair), and have an older save that I may need to go back to.