He left Jensen unconscious and called the police so they could arrest him and it seemed like maybe Dexter finally realized he was accountable for his own actions. Actually, he did realize that, but he's not cured. Quite the opposite, it seems. He left Jensen's house and went to get Clint, Hannah's father. He took the guy out on his boat and killed him, then dumped him in the water.
Clint didn't fit Dexter's code, so this is a pretty huge deal. Dexter killed him because he wanted to, plain and simple. Freed from the notion that he's at the mercy of some "dark passenger," and now willing to take ownership of his actions, it appears he's open to releasing himself of the code if it suits his interests, which means we may be seeing Dexter unleashed. We'll have to wait and see if that's what actually happens. It could be that Clint is just a one-time-thing for Dexter and he'll return to hunting murderers. Or else, he's on the verge of becoming a code-less serial killer.
Though he didn't come out and say it, it seemed like Hannah understood Dexter's meaning when he said her father wouldn't be bothering her anymore. Hannah not being able to kill her own father shows she does have boundaries. But watching her hug Dexter, my initial fear was that she might want to repay the favor to Dexter by taking care of Deb. (Previews for next week's episode suggest that as a good possibility).
Meanwhile, before Dexter killed him, Clint sent a voicemail to Deb tipping her off about Arlene Schramm, the witness to Hannah's murder of her camp counselor. So that cat's out of the bag. And Deb's obviously going to do what she can to see that Hannah's brought to justice.
Speaking of murderers getting busted, LaGuerta's still working with Tom Matthews on the Bay Harbor Butcher case. Tom brushed off the idea that Dexter could be the guy, but the more they looked into the situation, the more signs pointed to Dexter. Investigating the cabin where Doakes was killed revealed that it once belonged to Santos Jimenez, who was one of the people responsible for Dexter's mother's murder. That, added to LaGuerta learning that the Ice Truck Killer was Dexter's brother has her more convinced than ever that Dexter's the man. Tom agreed to talk to Dexter about the situation, though he still seems doubtful. That conversation's going to be interesting.
The last Brotherhood loose end is (presumably) tied up. Quinn and George had a confrontation at the strip club and George, thinking there was no way Quinn would just outright shoot him, was slapping Nadia around to antagonize Quinn. George was wrong. Quinn shot him and then quickly got Nadia to shoot him in the arm to make it look like he shot George in self defense. Deb seemed to buy the story but Batista, who was in the strip club when the shots were fired and knew there was too big of a gap for the story to hold up, seemed skeptical. This, added to Quinn stealing the evidence earlier in the season, may have raised some red flags for Batista. He knows Quinn's not being honest, but where's all of this going?
And finally, everyone knows Dexter's dating Hannah. Somehow it seems like that'll be relevant at some point.