Uhm, more like a few minutes at the end of the episode and surely the episodes which are forthcoming. The storyline sucks, because, as people have said, here is a guy who raised this kid and did his best and he wouldn't even let him explain how he saved his life.

Except Peter wasn't raised by Walter. Walter got sent to the mental hospital early in his childhood. He was mainly raised by his mother.

Besides that, I doubt someones first reaction would be to listen to a man who is essentially a kidnapper.

Didn't Walter abuse Peter though? I mean, shocking your kid with car batteries is considered abuse, right?

Walter is my favorite character, but I don't really see Peter's reaction unreasonable at all. I actually thought he was too calm if anything.