You found out that the bad smell was coming from the wall, it was a false wall and there was a crawl space in between the wall and that was where the bad smell was coming from. So you went in the wall to get the source of it and get rid of it. Wally stayed to make sure you wouldn't get stuck and to help if needed. But it was a long way down. When you tried to get down carefully you accidentally fell all the way down. Now you realized that you're also now stuck.