You don't even make the attempt. Scrooge got a glimpse of all he lost and all that would be lost. He made a concerted effort to change. We never did find out if the change stuck, but I'm no cynic. I believe it did.
Cops are like Scrooge.
They start out idealistic. But police work can be a cruel game. They must become skeptical. There is safety in skepticism. There is optimism in skepticism.