Does Nick not realize that he is contradicting what he just said about controlling his own destiny and life? It's possible the person talking here is actually future Nick, who goes by the alias Ambrose. By going back into the past, Nick wants to see if he can change his own destiny. (But then wouldn't the future be different, anyway? So how could future you go back in the past to fix things if things have already been fixed, and future you is already just fine? Don't ask us.)