For those curious, this episode is based in theme upon Pirandello's play, "Six Characters in Search of an Author" and Jean-Paul Sartre's play, "No Exit" (as indicated most obviously by its title), but, of course, with a Sterling twist.
Five very different individuals find themselves in a round room with no idea who they are other than the indication of their attire. A bell intermittently rings (perhaps also a Hemmingway allusion?), increasing the agony of their incarceration. The newcomer to the group, a Major, is determined to escape, while the others are resigned to their fate.
Unlike Pirandello, these characters don't even have a story. They have nothing other than the experience of the room in their consciousness, and no one to author their nonexistent story, so their position is even more hopeless than the characters in Pirandello's piece. Unlike both Pirandello and Sartre, there is no relationship involved between the characters and therefore no real conflict between them, though the theme of personal responsibility versus apathy is prominent in this story.
Though this diverges significantly from the storyline of the authors alluded to in the title, themes of Sartre and Pirandello (and many other authors of the twentieth century) come through with absolute clarity. This is very obviously a piece which addresses post-modernist perspective in the context of the Cold War era. There is also an emphasis upon issues of personal insignificance.
This is easily one of the best episodes I've seen, and still exceptionally relevant to current experience (as are Sartre and Pirandello). Exactly what makes a good piece of writing into a classic.