It's hard to believe his union would let him leave like that anyway. The chief was probably trying to keep it quiet, since he tampered with evidence to keep Dean on the force. I also think he saw Dean as not having anything on Nia because the captain was (sorta) by the book.
On the other hand, Dean just went full evil. The first time he worked for Nia, he was putting cops in danger, but mostly feeding intel to keep her drug operation protected. This time, he basically wrote Murphy's (and Max's) death sentence along with selling out Gene. It turns out he's the foil, so he probably won't be dying.
I know what you mean, but it's still funny to think that Jess has to redeem herself. I mean, is she redeeming herself for not letting Nia die the first time or not wanting to be co-drug lord with Murphy?
Darnell is Nia's brother. That's why she let him live. He might take over with her gone.
So, with all the bodies and screwed up meetings, this has skipped over Breaking Bad and landed in Sopranos territory. They're probably going to the Pine Barrens next week.