Did everyone forget that Nolan lost his chance at ever becoming detective...... Him and Bishop didn't follow protocol and both got a sheet in their jacket. Sergeant gray told him that from that moment on he would never be able to become detective. His golden ticket was used to become a training officer so that he could promote change in the department especially after what happened to Jackson. That's where he does and will do the most good. Yes he is good at solving crimes but detective is not something that he is able to achieve with that file in his jacket.
