I'll tell you what happened to me under Thunderfist the first time I played MM7. Fortunately, I'd saved my game before leaving the Nighon tunnels. My party entered the tunnels under the mountain, got past the 4-way intersection, chased by a couple of minotaurs, scooted up the NW passage, and found its path blocked by 3 eyes, spread across the passage. By the time they'd cleared a path past the eyes, the minotaurs had caught up - a severe case of whoops bang, oh nasty! My party got out with 3 dead, and the paladin on his last legs. Fortunately, I had some scrolls of Raise Dead, but that was a very close call indeed.