I'm confused... what happened to Bell? Where did Peter come from? I didn't see him rescued from the amber... or did I miss a scene?
Simon sacrificed himself to dislodge Peter from the amber, once it was shifted momentarily from solid to gas. They just didn't show who he pushed out, when it happened. As for Bell... it's a bit of a mystery. He's supposed to be dead. Yet, he was encased in amber, a signature of the Walternate universe. Perhaps he died but was then quickly preserved in the amber, just in case they might be able to resuscitate him? Or, leverage his brain somehow? They certainly intend to make use of his hand! I guess to gain access to some room using a hand-print scanner.
I wonder if this episode was a kind of continuation from the "future" (yellow?) universe, where Peter went to at the end of Season 3? Remember, Olivia was killed there by Walternate. When Peter used the machine to "heal" the universes, it may have inadvertently left the future timeline intact.
In any case, I too found the episode raised more questions than the answers it provided. It seems way too unfinished to be a stand-alone. I have to believe they'll do a follow-up later on. It would be kind of interesting to see it alternating with the prime story line. I really want to understand what happened to the Observers, why they changed so radically.