"Misses is finally coming out!" before the elf could be interrogated it vanished with a small quiet pop that made him KNOW that the elves might make their apparitions very loud. He grit his teeth but otherwise went back to the room and sealed his door, the elves could appear in the rooms whenever they wished so he had little fear of them getting the food to her. So the elves knew that she wasn’t human and knew it probably before the others. Considering her tirade for house elf rights maybe a part of her felt a connection to them and not just because some of Voldemort's plans were going to be quiet horrific to muggleborns. Much more than any quick or lingering death. All muggleborn kids would be grateful if their parents smothered them before he could catch them; thankfully none of that happened. 