Bayliss and Giardello in “Unfinished Business”

Bayliss

I didn't avenge Adena Watson's death. Now I never will. Never gonna know who killed her. I let her down, Gee.

Giardello

You're gonna hafta make your peace with that.

Bayliss

Let me ask you something, Gee. How do you know when to stop caring?

Giardello

I've been a cop a long time. I can tell you how to sweet talk a confession out of a stone cold killer, sidestep the politics of me and the bosses. I can tell you how to work a case until there's nothing left to be done but to file the paperwork. But the one thing I can't tell you, is when to stop caring.