I think they meant an illuminated room, but with absolutely no light being reflected by the wallls/floor/ceiling etc. So all the visual spatial cues would be m

I think they meant an illuminated room, but with absolutely no light being reflected by the wallls/floor/ceiling etc. So all the visual spatial cues would be missing, despite being illuminated, like being in an infinite space. I could see how that might be disorienting and strange feeling.