However, failing to send reinforcements doesn't mean the Mi Clan can't assist Mi Yang's actions. The Tang Clan, upon hearing of Tang Luo's ambush, will surely dispatch a Martial Ancestor to his aid. It doesn't take a genius to figure out the shortest point between two locations is a straight line. As long as the Mi Clan dispatches their top martial artists to blockade the corridor between North Mountain and Red Cloud Mountain, they can delay Tang Clan's reinforcement.
Even though Mi Yang's actions have undermined the plans of Clan Head, Mi Jin and Mi Shen, the two still decided to assist Mi Yang as much as they can, despite knowing the yield won't be as high as having Tang Luo fight Xiao Ziyu as planned and "accidentally" ending up killing him.
After all, Mi Yang has done more than one can count for the Mi Family, the top figure in the Mi Clan. Even if he acts out of line, all they can do is bear with him against their wishes.