Mormons are impressed by stuff and bureaucracy. That's part of the reason that there are so many people with titles, gotta wear neck ties, yada yada yada. Having a vault makes them seem like the government.
I've been in "the vault" and it's quite large. My boss at the COB took our little group there one day for a break from work. There was a lot of paper documents as well as microfiche films. Back in that time, most anyone could go in and see it; now it's very strict with security guards at the gate. I had heard a rumor awhile ago that it's also ready to use for the GA's as a refuge in the event of a natural disaster, war, etc. I'm not sure that's true, but it would make sense because of the vault's size.
I wonder if there's any phone service or wifi in there. Most likely, they have a complete collection of MoTab broadcasts, conference broadcasts, firesides, Mormon movies like Johnny Lingo and Man's Search for Meaning, various versions of the Temple movie, and Mr. Kruger's Christmas. How would it be to be trapped with just Mormon junk for entertainment? Wheat and dried milk and Tang, and some old freeze-dried food storage meals. Nothing to drink but water. It would serve them right. They would be sole survivors, with no sheeple to preach to or dominate. Probably, like when they travel, the Big-15 will bring along their entourage of servants, staff, and a camera crew.
I can imagine the luxury and opulence of the bunker suites! I envision a giant man-cave, with plush leather lazy-boys, and big screen TV's.
The Mormons will love it, as they love windowless places! What do Mormons have against windows? Are they expensive to install? Do they make a building less energy-efficient? Are they trying to prevent Mormons from spying on each other, and ivading each other's privacy? I think it's because Mormons have so much to hide.
They will evolve to become the futuristic "Mole People."