Didn't Care
Ryu closed the book he was reading. They had taken longer to find him than he thought, so much so that he had already been here for several hours.
The truth was that Ryu didn't know the rules of the Sect, but most Sects regardless of background, unless it followed some sort of obscure, degenerate path, would have rules against disciples harming one another. It was just basic common sense.
Of course, it also happened to be common sense that Ryu didn't care to observe. He had little patience for such things. He simply didn't care.
If he had joined the Sect through normal means, he would have, at most, crippled his "oppressors". But, since he had done so off the back of Old Wan, then he would act as he pleased. Commanding him around didn't come without its troubles.