Worked in a few kitchens when I was a teenager and those industrial dishwashers usually have a sink to the right of them and a flat surface to the left so you can slide trays of dishes through them from right to left. The dishwasher itself divides the dirty and clean areas so there’s no cross-contamination. If one were set up so that you just slide the tray in and back out the same way I don’t think that would meet hygiene standards.