I just recently picked up on my IWD2 game that I left off years ago. So note that my memory of all the details of the game in general is vague.
My game picked up on the 2nd level of the dragons eye, at the alchemy lab. It was the first time I'd been there and the whole level wasn't clear yet. So I cleared it and most of the next level, talked to the right guys, kill the wyvern, get the modified mandrake root, etc. But when I go back to the lab, the doctor is not there and the lever still doesn't work. The note you get there indicates you need to "wait for him" to get back, but I've waited a long time and nothing changes.
So can you think of any other plot points I need to hit or is there an alternate way to find him? Reading walkthroughs and searching online leads me to believe this is not a common problem, so I must just be missing something, but I don't know what!