Sorry, Dave, but that’s not the Twilight Zone bomb shelter story I think of when it comes to you. This is:
Millionaire Paul Radin invites three people to the bomb shelter that he has built. He greets them politely but without genuine warmth as he holds a personal grudge against each of them. One is a high school teacher (Mrs. Langsford) who failed him when he was caught cheating on a test and attempting to frame another student to avoid the consequences; the second is Colonel Hawthorne, who had him court-martialed when Radin endangered lives by disobeying orders; and the third is Rev. Hughes, who made a public scandal out of a woman who committed suicide over him.
Radin, with the aid of sound effects and fake radio messages, convinces the trio that an apocalyptic nuclear war will occur in just moments. He offers them refuge in the shelter if they do one thing: apologize for their actions. All three refuse his offer and leave the shelter, valuing their honor above their lives and preferring to spend a last few moments with their loved ones or alone than to live with Radin.
Mrs. Langsford, still believing Radin will survive but be left alone, tells him to try to cope. She tells him that he has spent his life deluding himself about his own character and what is right and wrong. Radin screams hysterically that this is not true.
Suddenly, the sound of a bomb detonation shakes Radin's shelter. He takes the elevator to the surface and emerges to see the world devastated and in ruin. This twist ending is given another twist, however, when we learn that Radin, devastated by his hoax's failure, has lost his mind and is only imagining the total destruction. Radin sobs helplessly at the foot of a fountain outside his intact building while a police officer tries to aid him.
Mr. Paul Radin, a dealer in fantasy, who sits in the rubble of his own making and imagines that he's the last man on Earth, doomed to a perdition of unutterable loneliness because a practical joke has turned into a nightmare. Mr. Paul Radin, pallbearer at a funeral that he manufactured himself in the Twilight Zone.