There is an episode in Woody Allen's movie Take the Money and Run. A lady is being interviewed about Virgil, the main character in the movie. And she goes:
Just to think that that idiot was a criminal, I just can't believe it. There was a mind working in there that could rob banks. It's phenomenal. Once I said to him, "what do you do?", and he said, "I rob banks". Go no, right!
I hope you get the mood of this passage. So, what does this "go no" phrase mean here?