How has Winston's environment changed, what does he do with his time, and how does he show his obedience to the Inner Party?

Winston is being held in a prison cell that is bleak and frightening in its isolation.

He spends his time repeating 2+2=5. "God is Power" and"Freedom is Slavery" to remind himself of the pointlessness of resistance.

He complies with them by betraying Julia to escape more torture.