Diana's existence would obstruct that method and he would not be able to harm the Chens in the slightest.
If Maxim lost his wife due to Ryle's retaliation, then both Maxim and Hazel would come at him with daggers. That was not a very ideal situation that he would prefer to put himself in.
So, he wanted to drop the hot potato back to his friend or at least act like it was a big deal so that Maxim could coax or comfort him a little but he never would have thought he would be tricked so flawlessly.
