is there a possibility that the seatbelt could fall in the toilet and get wet and er soiled?
would you then use the seatbelt?
in airliners, there are oxygen masks for all seats plus a reserve mask at proper intervals.
Now I do think that the lavatory should have heavy padding all over the place in case of hitting turbulence while in the lavatory in an awkward situation.
I know of one incident in which the plane hit severe turbulence without warning, and the SEAT BELT SIGN WAS ILLUMINATED. ONE person didn't obey the sign and was walking to the lavatory ...he was tossed around the cabin, breaking his neck and becoming paralyzed.