I've done a bit of caving, but nothing like this..! That said, it probably doesn't seem as extreme once you get going. Sense of depth, space and darkness is relative, space up to a point. What seems tight from here isn't so bad when you're in it - and of course when you're halfway through a squeeze you have a big incentive to get the other halfway..!
woah that's one deep cave! The map even looks spooky. It must reach down to the center of the earth or Hell or something!That is a great template for a cavern complex.