We assume you know how to use the restroom in the usual sense so were gonna cover how to use it in the tradecraft sense.
Public Restrooms offer you many opportunities in an operational environment to further your personal preparedness, security and situational awareness.
Check out S2 Underground and their videos on LBRY for more quick tradecraft tips.
After you are seated make a trip to the rest room. This gives you a reasonable explanation for walking around the restaurant and getting the lay of the land.
Along your way this allows you to scope the other people in the restaurant as well as the layout, alternate exits, blindspots etc. All while having a reasonable explanation for your actions if you are being watched.
In most cases the rest rooms are usually in the back near employee only locations. In restaurants this means back of the house like kitchens and so forth. By taking a peak in there on your way to the rest room you can get a glimpse of what the back of house staff uniforms look like which furthers your situational awareness.
You will know if someone coming out of there may or may not belong and whether you need to pay attention to them or not.
Another benefit to consider especially if you are being surveilled is that the rest rooms are usually one of the few places in a city that is not under cctv surveillance. Most people don’t think twice about someone changing clothes in the bathroom.