I've talked to Dr. Elrath, and he's left the house (pushing me out with him). Now I can't get back in, because I can't select the door. When I put my mouse pointer above the place where it's supposed to be, nothing happens. It's as if it's all just a solid wall. So I can't unlock it with the key I've got or try to pick the lock, because there's "nothing" for me to click on.
Also, it's a long time since I first entered the house and I do not have any earlier saves, so I can't reload and put my pyramid in the house.
Any suggestions?