It’s a pretty vivid part, one of the most important parts of the book. Winston tells O’Brien that with all that he had been through, no matter what they did to him, at least he hadn’t really out and out betrayed Julia. He was hanging on to that, as his humanity, the one thing they couldn’t take from him. And O’Brien thinks about this, and says, you are right, you haven’t.
The next day he puts a rats in a case over Winston’s face, and his face is enclosed with them. As soon as they eat through the thin barrier separating them, the rats will be trapped in the enclosure with just Winston’s head and face, and they will claw and naw on his face until he dies. And so they finally tap into his worst, most primal fear, and in that moment, he yells out, no don’t do this to me, I was not the worst traitor, do it do Julia she is the one who deserves it. And that is when O’brien is finally satisfied, and Winston finally loses every last scrap of who he was, and he will never get it back.
It’s the most chilling part of the book.
