And, you if by chance you do break the next rule of look ahead and not at the other guy, you only are allowed to look each other in the eyes.

Guys learn this without being taught. No matter what socially/politically correct spew that comes out of their mouths outside the bathroom door, once you enter the rules are the same for everyone, everywhere.

If you are spatially aware (like a Seal or Spook), you go to the stall where you can’t get attacked from behind, but that is skill level 10 for dangerous people.