Well, if something needs to be done in the future and they want to ensure things are done right or have a back-up plan to get rid of the Observers, then I can see Peter and Olivia separating. Also, if Olivia is pregnant, she would have to stay behind and raise Etta. Peter could go forward for his child's sake to do whatever it is that has to be done. From the promo, they mentioned that "your team" had discovered a way to get rid of the Observers. Peter and Walter may have to deploy that mechanism.
I still think we need to know what it is Jones needs Olivia for because he seems to know she has endless possibilities. Is it also possible that Olivia seals in Walter and Peter to keep them safe and not be a tool to be used against her? Her power works best with Peter. If Olivia is pregnant and does not know it and is at risk of death in some fashion, will we see what happened to AltLivia, happen to Olivia in that she her pregnancy must be sped up to save Etta. Could Lincoln and AltLivia raise Etta to keep her safe?
I can't help think of the episode "Fracture" in which Gordon is using "Tin Man" as a way to send "them" (the Observers) a message:
RAYMOND GORDON: (steadfast) ...meanwhile, we go through our lives unaware. The enemy is among us and nobody's doing anything about it. We don't have any idea the end is coming. So we had to take matters into our own hands. We had to send them a message.
BROYLES: What was in the briefcase?
RAYMOND GORDON: They told you I was crazy, didn't they? The Pentagon. They said I'd had a psychiatric break. I told them what I'm telling you. That they are here. Collecting data. Making observations. That's what's in the briefcase. They've been planning for war. And they've been passing the information via courier right under our noses.
(as the interview continues, a young man in a long dark coat walks into a diner and delivers a briefcase to a seated man, then leaves)
BROYLES: Who are 'they'?
RAYMOND GORDON: We don't know who they are. But I can tell you what they want. They want to exterminate us.
(the man seated in the diner pours an entire container of black pepper over his roast beef and jalapeno sandwich, then opens the briefcase he received from the courier)
RAYMOND GORDON: So they're studying us... our culture, our technology, our science... and they plan to use it against us. One way or another. We'll find out who they are. But by then, I suppose it won't really matter.
(The Observer pulls images out of the briefcase. High-tech surveillance images of one Walter Bishop)
RAYMOND GORDON: Because whatever's in those cases is gonna destroy us all.
Somehow Gordon picked up on the Observers. He seemed to know how they were relaying their info in the brief cases and who was transporting that info to other Observers. How did Gordon find out? He knows they are planning for war. Is this the same war between the universes or one that is still on the horizon?
Hasn't Peter been compared to a "tin man" in forum discussion? Can he be some weapon against the Observers in some fashion? In Wikpedia it says:
n the original The Wonderful Wizard of Oz book of 1900, the Tin Woodman is depicted as a formerly human worker who has been stripped of his humanity (his heart especially) and dehumanized by industrialization. The Tin Woodman little by little lost his natural body and had it replaced by metal; so he has lost his heart and cannot move without the help of farmers (represented by the Scarecrow)
This description sounds like the Observers as well if they are part machine or have parts of them replaced as described in some "technological singularity" in the future where humanity is part machine via nanotechnology. Is that why Peter is sent forward? Did he also modify himself with nanotechnology to do something to get rid of the observers? Will this Walter interfere and cause the end of the world as "Fracture" may imply (Walter is different in this new timeline) or can he make such a sacrifice again?