I can’t remember the episode right now, but one of Rod Serling’s original Twilight Zone episodes was about just this. An alarm was given that the Soviets had fired nukes at us. One family had a fully stocked bomb shelter and wouldn’t let the neighbors in- they only had enough provisions for themselves. It got quite ugly.
I won’t give away the ending, but look it up if you can. Some of you might remember it.
Good episode. Saw it recently. The title was “The Shelter”.