Once upon a time ago a friend of mine was the person who sits in the nuclear silo waiting for the red phone to ring. We were chatting and she told me one of the most wild things I've ever heard.
So the bunker itself is basically an egg sitting inside of another egg deep underground. It's got these shock absorbers in case there is some sort of bomb strike or natural disaster (mostly I think bomb strike) so that the systems and people inside aren't affected.
In the event that something happens and they need to make an emergency escape, there was a hatch that the two people in the bunker had to crawl out of to get onto the top of this egg and into the like 3 ft of space between the egg and the actual Earth.
Once there there's another hatch at the very top that opens to a shaft with a ladder. To keep that space from collapsing it is filled with sand. The hatch opens with two wing nuts (maybe bolts?) and is an inch thick. Once you have gotten the second wingnut mostly unscrewed it's a matter of timing to avoid being knocked unconscious. When you open the hatch (and as she was the senior officer she told me that this was something she would obviously allow her junior colleague to do) the sand also immediately falls down and fills up the space around the egg.
There was some debate on if there was enough room around the egg for the amount of sand, so it was generally seen as good practice to go ahead and start climbing while the sand was still falling. Basically swimming upstream.
Once you got to the top there was another hatch that required quite the series of things to open and of course only opens from the inside.
That hatch had been paved over to put up a basketball court.
