There's a good story about that... https://medium.com/@JohnLeFevre/the-roadshow-aka-the-worst-p...

Just buy a 50¢ adult diaper and go to the bathroom without leaving the comfort of your seat.

That seems to be the option for $3M jets as well. You have to get up to $4M to get a door in front of your toilet.

Here's the $3M toilet option (Cessna Citation Mustang): https://blog.privatefly.com/us/wp-content/uploads/2014/11/mu...

not really very hard to imagine. money doesn't always equal good at logistics...