P5 rated tiles are not necessarily for outdoors, but for high traffic areas. If you want to put them in your bathroom, then why not. But why would you want them on your walls.?

https://www.beaumont-tiles.com.au/tile-ratings

Tiles that are considered external are often thicker for added strength. Talk to the tile shop or your toilet to understand impacts

@Kate You must have a fancy toilet, if it offers advice??

Gosh what a thought Imagine if they could, all kinds of sh... I meant tiler.

Thanks all! I want the same tile both floors and walls. Unfortunately, I cannot find an equivalent wall tile, so I have tile the P5 up the wall. Thanks Kate for advice re thickness of tile! It never occurred to me to check that!