Do you consider her to be one of the villains on the show ?
I think she's really a complex character. I mean she really thought that Assemblyman's career could help the police do a better job in the future right ? If so, lots of innocent would be spared a lot a grief and bad guys would be put in jail more easily, right ?
Put yourself in her shoes : if you think that one person is the only one who could help saving hundreds of people in the future : would you cover the crime of one of his family member ? One innocent sacrified in order to save thousands ?
I remember liking her character a lot, despite everything. I could sense her humanity and it was clear enough that her motives were not your usual greed for power or money. Characters whose choices are driven by a "higher purpose" are always extremely complex and controversial, because they move in the realm of ethics, and because their motivations could be ours.
This said, I personally consider the life of one single innocent person more precious than that of a thousand who could benefit from his/her death in the future. Unless that single person was me - in which case we might negotiate - I could never sacrifice a random person for a future which hasn't been written yet and of which we know nothing.
I think she's part of the evil ones before she was a chief but, had a change of heart? She's just playing it safe with the assemblyman maybe because she's afraid to die too? I personally think she's a good person, I mean shes been helping Daegu a lot and she cares about him.