Things to ponder - in the Twilight Zone video, the shelter did NOT work, because not all threats were guarded against. Sure, he was protected from flash, blast and fallout, but not a 2x4 battering ram. The point of the TZ episode was not that a shelter was a good idea, but that the real threat to human survival was other humans.
Regardless of your level of prepping, if the S were to truly HTF, unless you're in a true bunker (like that place in Virginia, below the resort) you're going to have a hell of a time.
Remember - everyone else will do what you're willing to do, to survive. You might have an edge over a lemming, because you're thought about it, and "prepped," but if it's 50 of them to one of you, and 75% of them die off, it's still 10:1 against you.
Make sure you have a backup plan, because your first one won't survive contact with the enemy.....