First cycle of the dishwasher is just a hot water rinse to get a head start on removing debris that gets drained away. Then it refills and deploys detergent and spends most of the rest of the time in this cycle before rinsing and drying. So, I mean, I don't recommend it, but it will be drained a few minutes into the cycle and the dishwasher will actually clean with detergents after with no pee left. So, it really won't hurt anything besides your relationship with your family/roommates.