Hmmm... I wonder if painting the walls and ceiling in a landscape & night sky would help. Maybe a desert scene to give the impression of distance?If you're claustrophobic you might look into some of the underground fiberglass shelters that are not rectangular. They are white inside and there are no corners so it has a different "feel". I'm not claustrophobic, but a friend of mine who is once said that it wasn't too bad.
Just a thought. Luck.
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