so in the world of fallout we know aliens exist and in a pretty big way you even get a gun from them, but their is a DLC were you get beamed aboard a zeta mother ship and they have cryo tec like in vault 111 so what I'm thinking maybe vault tec had some help in building vaults and I don't think its that outlandish to say this because on that mother ship i mentioned earlier their was people from different times their is even a samurai which shows us that they can store humans for way more then 210 years and that they have been around for over a century so vault tec probably got hold of some of that cryo tec and reversed engineered them so they could make them this clearly didn't work to well because well if it worked properly fallout 4 would never have happened.