Fringe: Reciprocity

First of all, a giant pat on my back that they are using MY name for Fake Olivia: Fauxlivia. Woohoo! Clearly, they read my tweets...
Lots going on in this episode - the main story is the link between Peter and the machine, while the sub-stories are the assassination of the shape-shifters and the relationship between Peter and Olivia. Peter and the machine interact in the very beginning of the episode - the machine changes position, and Peter gets a nosebleed. For a while, it appears that the nosebleed is the only impact to Peter, but of course, by the end of the episode we know that there has been a bigger change. There are hints all through. When Peter first sneaks home, right after the credits, we know that he's up to no good. Later we see him carefully eying Dr. Falcon, presumably because he already knows that Falcon is a shape-shifter. Then there's Peter's resistance to Olivia reading Fauxlivia's files. He says this is so Olivia won't think badly of him, but in reality, it's because he knows Olivia will crack the code. And then there is the obvious lie to Olivia, immediately after she offers him a relational olive branch. (Note to Peter: lying to the woman you love just after she forgives you is not a good strategy).
A few important repercussions of this main story. Walter and Peter are now holding a secret from the rest of the team. If Walter's theory is correct, then what will happen to Peter in the future? Will the weaponization continue? What else has Peter gleaned from Fauxlivia's file and how will he use it?
Sub-story of shape-shifters. I really enjoyed how this ties back to Peter's shady past. Naturally he would have access to guns with silencers, know how to break into houses, etc. He was basically a criminal before he hooked up with Fringe division. This episode is a nice reminder of all that. Then there's the question that Walter asks him: if what he's doing isn't wrong, then why does he keep it a secret? I think there are two answers to this. One is that Peter keeps it a secret because that's in his nature. Thinking of that book in the last episode, Peter wants to find his own answers - he acts independently. He knows that telling the others will delay the mission and possibly jeopardize its efficiency. The other possible answer is that Peter does feel shame over what he's doing. After all, he's deceiving people he loves. It can't be easy to watch Olivia's frustration over being just one step behind.
Sub-story of Peter and Olivia's relationship. I really like how they're handling this. It's very believable. Olivia has had time to get over the sting of Peter's failure to recognize her alternate, and now she's able to think about what it must have been like for Peter. Yet at the same time, Peter is now throwing complications into the situation. He's read Fauxlivia's notes, so he now has a better understanding of what she was really thinking. How does it affect him, to realize that she was truly starting to have feelings for him? Is he wondering which Olivia he cares about? In addition, he lies to Olivia and is keeping a pretty significant secret from her. He must know that this will be a pretty big problem for her. Is he intentionally keeping her at a distance while he sorts through his own emotions? This is a great way to maintain tension between them without getting all Rachel-Ross on us.

Loose ends:
Peter's heart raced during the test. Nerves because he knew Falcon was a shape-shifter? Or something else?
Broyles' near accident while driving to Alpert's house. Last time we saw that, Olivia went to the other universe.
How did Peter read those hard drives?

Funniest moments:
1. When Walter "shows dominance" at the lab.
2. When Brandon is held at gunpoint and asks if he can swallow.