Although we have long ago guessed it and even described it (sometimes at length…), it’s interesting to finally see how Walter’s guilt developed and where it stemmed from. By the same token, it’s interesting to see where Walternate’s current determination and drive stem from.
While Season 2’s episode “Peter” showed Walter’s real intentions – i.e. to heal Peter 2.0, not kidnap him – this episode showed the real reasons why Peter was never taken back: although he tried, Walter couldn’t figure out how to take Peter back to the Other Side. This makes the ongoing discussion of good and evil in Fringe all the more interesting, as it makes Walter seem even less ‘evil’ than he seemed initially in Season 1.
This subplot underlines a related interesting concept in that often, lies that in Walter’s words, are “supposed to be a temporary measure” can easily become a way of life, causing immeasurable suffering and harm. When you “consider that the worst of qualities and most odious of attributes, which is the foundation of all evil, is lying”, then one can understand how Walter went from the loving father in the episode “Peter” to the father he was described by Peter as having been, back in Season 1. Once again we realise just how the road to hell really is paved with good intentions.
Then again, perhaps Walter couldn’t find a solution to the problem because deep down, he didn’t really want to return Peter 2.0 to the other side. If this is the case, then subconsciously he might have spent many years self-sabotaging his work so as not to solve the problem of travelling to the other side, until he performed the ultimate act of self-sabotage: the fire that killed the lab assistant and sent him to St-Claire’s.
This episode helps clarify some of the complex reasons why Elizabeth started drinking. It was partly to numb the burden of the guilt at the lie she had to tell Peter, and partly to numb the pain of making him suffer because of said lie. We can only imagine what Elizabeth went through before she finally committed suicide; imagine how unnerving it must have been for her to look into the eyes of the boy that looks exactly like her dead son and lie to him throughout all these years, and to withhold the words “You’re from another Universe” which could have alleviated so much of his pain.