who keeps finding absurdity in an absurd situation. I guess that's what they call the trivialities of fiction! ;)

I agree on the triviality. In that case, nothing of a sensible explanation whatsoever in a biological sense is needed, I think. Does the story function then without taking in the "oxygen level"? You could have gone even more wild to keep finding absurdity in an absurd situation:)

To bug you a little further, I don't see any distraction in this story, which I read as a standalone. His inner world would allow a distraction if he were already befuddled and delirious, not really aware of any distress. But then I end up back at the beginning, where he is trying to free himself. A bit half-hearted, the chap, HaHa!

Related to anything goes:
My husband and I frequently argue about the utter arbitrariness of science fiction films involving time travel. Basically, you can tell anything without following a certain logic. Like Douglas Adams did, for example, and created a complete fantasia.