This is not a logic puzzle.
Let's say that something bad happened to you, and therefore you are afraid of the world. Or certain aspects of the world. You're afraid of being hurt again, which is natural.
To protect yourself, you build a cube and place yourself firmly within. You know, or at least presume, that behind five of the sides, hurt and pain lie in wait. The sixth side is the only way you've preconceived as being able to leave, because the sixth side is behind you and might lead back to a time when things are safe. Or maybe it opens to a future where things are right again. However, we all know that no doors can open into the past, and that the future is nearly unpredictable; therefore, that sixth side has been barred from the outside by forces beyond anyone's control.
How do you get in from the outside? How do you get out from the inside?
To protect yourself, you build a cube and place yourself firmly within. You know, or at least presume, that behind five of the sides, hurt and pain lie in wait. The sixth side is the only way you've preconceived as being able to leave, because the sixth side is behind you and might lead back to a time when things are safe. Or maybe it opens to a future where things are right again. However, we all know that no doors can open into the past, and that the future is nearly unpredictable; therefore, that sixth side has been barred from the outside by forces beyond anyone's control.
How do you get in from the outside? How do you get out from the inside?