thoughtcrime

He is willing to risk nonexistence because his existence is--well . . . nonexistent? His life is nothing. He has no one to love, no goals in life, and no sense of who he is as a human being. So his current life is meaningless. Thoughtcrime--writing to the future, entering into the affair with Julia, contacting O'Brien about the rebellion--gives his life some purpose. If he loses his life in the process, well, at least he lived for something and died for something.

Of course, O'Brien knows all this and prevents Winston from having any purpose. That's why he turns him into a BB enthusiast before setting him "free." The only meaning in life can be BB.

Really frosts ya, doesn't it?

Life in Oceania is boring. There are no risks. No excitement of any kind. No goals, no challenges. Maybe Winston wants some kind of adventure--something difficult and risky to give his life meaning or at least to challenge him. If he wins, what a big victory. Maybe then he can lead others against BB.

I think he is very tired to live in that society as it is, not only for himself, but also for other people, he really wants things to change in a better way, and therefore he is willing to risks a lot, also Julia is, at least as the novel proceeds, he is really to risk, his own dead, and thereafter his nonexistence!