"Yeah," Hopper says, taking a step toward the guy. "You want her to tell me? A girl knees a guy in the balls when he's got her cornered in an alley, there's usually a damn good reason. The kind of reason cops don't take too kindly to."

The fact that he's technically not a cop, not in Darrow, that doesn't really matter to him right now. It just means if he ends up having to punch this guy in the face for being a creep, he's not going to end up getting written up or suspended for it. Maybe he ends up in his own jail cell if the guy decides to press charges, but that's not about to stop him from stepping in either.

The girl makes him think a little of Nancy. The defiant tone to her voice, the way she steps in to defend herself without a thought. He likes her almost immediately.