. What is the central theme of "No Exit" and how does it relate to existentialism?

A month takes a matter of minutes in Sartre's hell. In other words, the relationship between the characters and the world of the living is perpetually off-balance. When Garcin says that his wife died a month ago, he qualifies the statement by saying, "Just now." Indeed, a month ago is just now; the characters of the play soar through time, and even their visions of the world below are only temporary - fleeting images doomed to fade to black, transient sounds fated to fall silent. It is perhaps ironic that Sartre suggests this kind of temporal structure within the one-place/one-time dramatic idiom first proposed by the ancient Greeks.