You can see that blind spot in the piece where the author states there are only four ways out. There is actually a fifth, which is currently the one being used. At the moment Bejing discounts 'foreign currency' into Yuan and distributes it to factories that export. If foreign entities fail to buy that output Bejing can simply discount 'other assets' instead at the central bank, distribute it to the same firms and stick the output in a shed somewhere. The result is the same monetary circulation within China in Yuan.