When Johnny is in the casino watching the roulette game, the ball is circling the inside of the wheel, but the wheel itself is standing still. A roulette wheel never stops moving while the table is open.
The men's room in the casino has no sign on the door or any other marking indicating that it is such. The standard round door knob, which few if any restrooms have, further disguises its purpose. Particularly in a building populated by so many wealthy, international customers, the restrooms would be clearly identified. It looks like a storage closet.