Mu Tiange had never given up on dealing with Ye Xunhuan. Since the moment he fled from Jiangzhong City in a dreadful state because of Ye Xunhuan, he had sworn to completely destroy Ye Xunhuan!
This could be seen from the beginning when Mu Tiange was looking for an assassin, but he had not succeeded until now.
The humiliation of Qi Shijie's son, Qi Shijie, gave Mu Tiange a glimmer of hope, yet he made no move and just watched.
He wanted to see what Qi Jieyu would do, or more precisely, to see if Qi Jieyu could eliminate Ye Xunhuan.
But until now, he had not seen Qi Jieyu manage to do anything to Ye Xunhuan, which made it clear to Mu Tiange that it wasn't that Qi Jieyu didn't want to avenge her son, but quite possibly that Qi Jieyu had no means to handle Ye Xunhuan.
This resulted in Mu Tiange also making no move, but rather honestly staying in Jinmen while still keeping an eye on Jiangzhong City, or more accurately, on Ye Xunhuan.