Suppose the fallout shelter would guarantee your survival. Suppose furthermore that the massive meteor storm or whatever it is guaranteed to save your life from is guaranteed to hit the planet (or whatever) in five years. How do you feel about your discount rate in this scenario, with the other variables stripped away?

Suppose furthermore that fallout shelters are expensive enough that you either spend the five years living a very spartan existence, which will continue after the fact, or living it up with every luxury you've ever denied yourself in the five years you're going to get.