I think Louis Koo is a spy for four brothers of Michelle Ye Ann. Michelle Ye, Huang Lei and Louis Koo belong to the same school, and the four brothers belong to the same school. Although they are all beneficiaries of small houses, they don't really cooperate with each other. They always want to kill each other and get greater benefits. In order to truly gain the support of the four brothers, Louis Koo took the initiative to crash and destroy Ayuan. However, this action also cleared the way for them to build houses (and helped Michelle Ye), killing two birds with one stone.
After Louis Koo got out of prison, he still worked for Michelle Ye. It is not that he wants to kill the four brothers, but that the four brothers want to grab more wealth from Michelle Ye. Louis Koo is clearing the way for Michelle Ye, so he must stand with his four brothers.