The way I see it, even if you somehow believe that relieving yourself is somehow sufficiently hygienic that it doesn't require you to wash your hands in and of itself, the fact is that ordinary activities of everyday life do soil your hands, and you should probably wash them a few times a day even if you never saw the inside of The Smallest Room. So why not use bathroom-time as an excuse to get it done? I mean, you're already there, there's a sink all ready for you to use, and that way you'll get in a few hand-washings a day. Sort of like a biological alarm-clock, telling you it's time to wash your hands.