Through wheeze and cough..... he stayed dry

When Mason first got sick I went back to putting Pull-ups on him for fear he just won't be able to control himself. He amazingly still kept the Pull-up dry and told me when he had to go potty. He had been dry for over two weeks so I think he is officially "potty-trained". However, due to being sick there was a lot of whining and stubbornness today. There was also a moment of blatant peeing on the floor (literally 4 feet away from the potty) because he was mad at me. Where or where do my kids get that mule-like stubbornness?