Ghostbuster, you should have written Ep.3. It would have been considerably better than what George pooped. Your idea for the cave is really clever.
My only expectation was that it was going to be better. When it came out, all the reviews were pouring in saying "at last! finally! the episode we've been waiting for! it's great! 10 stars!". But when I saw it, I thought it was the worst installment of the entire saga, and a total unmitigated crapfest. I had actually enjoyed Ep.1 enough to see it three times, saw Ep.2 once or twice and thought it was kinda fun. But Ep.3, I literally almost walked out of.
Good people turning to evil is an age-old theme that has been done successfully in thousands of movies. There were so many ways it could have been done. George managed to find just about the only way to screw it up.