Well, it all seems a bit unrealistic, specially with the guy not writting the last page with the so called "answers". If they died, I suppose someone would have somehow removed the site.
I just think that these guys heard some natural sounds from underground, and because of fear and darkness and the tension of the moment they thought too much about them and thought they were things they were not.
I wish I had some kind of adventure like this, but I don't think I could stand going through such a small passage where my whole body squeezes and I can barely move, I would be too scared to be trapped there or not being able to get back. If I were them, I would have worked on the whole a lot longer in order to have a better way in and out of the cave.