Originally Posted by HDMe2
Why was Bell the bad guy? Was the previous timeline's Bell also a bad guy?
Was this timeline's Walter a bad guy before the brain removal?
I wondered about Bell too until he elaborated. It seems that in this universe he was completely taken in by Walter's ideology and his terminal disease was the trigger to crazytown.
Walter removed parts of his brain in this universe for similar reasons as the original timeline. In the original timeline he didn't like who he was becoming and didn't want to see a repeat of the same mistake he made with Peter.
In this timeline he was so wracked with grief about losing Peter twice that he came up with the universe merge in a fit of anger at cosmic injustice. He didn't like who he was becoming or the plan he had created so he suffered the same surgery.