Wow, that was probably so surreal for you and something to witness! I've never given rats a thought but had one (apparently they are solitary animals as learned this later from poo droppings) in the attic. At the same time had a wasps nest and thought it was the sweeping sound coming from the nest. Then the scratching/scurrying noise came along waking me up every morning above my head at 3, 4, 5, 6am every morning and I got to the stage at not wanting to go to bed at night! Had pest control in and they could say it was one rat as there were poo droppings in one place. Apparently, rats do their poos in one place unlike mice who poo everywhere!