I used to have an outdoor shatter in (or should I say outside) my old place.
Left hand door contained run of the mill squatter. I'd only enter that one when the situation was critical.
Right hand door was home to a brand spanking new piece of porcelain and a shower.
Please note. One should consider sound proofing such a convenience. I'd occaisionally here the neighbours sniggering when the bowel movement was extra fruity.