1984:Julia and Winston ... who gave in first?

When I read the ending of 1984, my first interpretation was that Julia had been the first one to cave in to O’Brien’s demands—very suddenly, at that—and renounce her love towards Winston. Thus, when I read the denouement, the chance meeting at the pub, I felt somewhat contemptible towards Julia. After all, according to O’Brien, she betrayed Winston “immediately - unreservedly.”

At the pub, Julia explains to Winston as to the reason of her betrayal: “Sometimes...they threaten you with something - something you can't stand up to, can't even think about. And then you say, 'Don't do it to me, do it to somebody else, do it to so-and-so.' ... And after that, you don't feel the same towards the other person any longer.” I interpreted Julia’s explanation as being contrite, guilty for giving in first.But upon closer inspection, it made me doubt whether she really did give in unequivocally. It was easy to scare Winston because he was scared of rats, but what could Julia be possibly be afraid of? She seemed to have more bravado than Winston. Julia was described as having “a long scar, partly hidden by the hair, across her forehead and temple.” I mean, after Winston gave in, he was still scratch-free, but Julia probably had to endure the pain of those scars.

Could it be that psychological shock wasn’t enough, and the State perhaps run out of ideas and had to resort to physical violence or mutilation in order to quell down Julia’s desires? Perhaps they tampered with her brain in the literal sense?