Quote 13
I explained, "He seemed to think I'd killed Dinah Brand. […]"
"Well?"
"You mean, did I kill her? I don't know, Mickey. I'm trying to find out." (26.76)
This is the moment of reversal when the Op goes from being the hunter to the hunted. He is wanted by the police, and he can't even remember if he killed Dinah. The line between villain and hero is at its most hazy in this moment.
Quote 14
"The Continental's got rules against taking bonuses or rewards," I said. (7.78)
The Op's professional code of ethics forbids him from accepting money as a bonus or reward. We can see here that the Op adheres to his own set of rules, even when there's no one around to keep him accountable.
Quote 15
"You haven't forgotten that your check was to cover the cost of investigating crime and corruption in Personville, have you? […] I'll give you nothing except a good job of city-cleaning. That's what you bargained for, and that's what you're going to get." (7.81)
The Op promises that he'll give Elihu his money's worth and bring back a cleaned-up Personville. The Op isn't someone who can be bought with money. In particular, he takes pride performing his job well.