One problem with that theory — he has been wearing the sainted all-saving mask within the time window for his exposure. Besides, the mask-wearing imperative is designed to keep from giving the virus to others, not to keep from getting it from them. The ordinary cloth masks have ~97% transmissibility of something the size of a virus. Others are a bit better, but only the cumbersome and uncomfortable ones, which are both expensive and hard to find, provide any real protection to the wearer.