To me it has deep existential meaning. "There's no way out of here, when you come in you're in for good. There was no promise made, the part you played, the chance you took."
That alone can be interpreted many different ways but when I heard it the first time I was filled with extreme existential anxiety. There has always been a suggestion when looking around for life's great meaning that this is the hell we all fear. Endless cycle of birth and death. There's no way out. Now my interpretation is just that. An interpretation.
It likely was a song he wrote about Floyd and feeling like there is no escape. The great thing about this song is that it can be applicable to almost anything. That's real art.