Summary: The three sinners tries to escape from each other in the small room with "no exit," but when the door is finally opened, no one leaves, because they don't know what's out there. The world outside the door represents the unknown. They have chosen "hell"-in which they can see each other and confirm their own existence-rather than the unknown.
My Thoughts: All we've got is the lives of ours and others. We can never escape from others in life-regardless of how much they may devastate our existence-because we need them to provide us with the basis for our existence. Since that's how it is, rather than being pessimistic about it, maybe it's time that we tell ourselves not to fear others' scrutiny and instead, "affirm this world" as Nietzsche's ubermensch.