I couldn’t do it either. I went inside a sub eons ago at a museum and couldn’t get out of there quickly enough. I started thinking about being in such close quarters deep underwater and just about lost it.
It gave me a healthy respect for those who can pull it off.
Even if they can be a half a bubble off at times. LOL
Maybe that's why they are called bubbleheads. LOL!
I believe there is a Russian sub next to the Queen Mary in Long Beach, CA...I went with everyone else, against my better judgment. I wanted to run out, but at least we kept moving and I was able to keep it together. Can’t do little spaces. I would be in the looney bin. The “no escape” is the issue for me.