FEAR AND SPIRIT IN 1984 GEORGE ORWELL?

They used his deepest fear (rats) to cause him to betray Julia. The fact that he hadn't betrayed her up until that point was the single thing that was keeping him sane and protecting him from their attempts to brainwash him, after that his spirit was completely crushed and he could no longer resist. I can't really think of anything beyond that, which is very obvious. It's not a scene that leaves a lot of room for interpretation, I think.