I only just caught up on the second season; where I'm confused is this: When our Olivia1 (Bell's Olivia) found Peter with Charlie and knocked Charlie out, she was Olivia1, and since then was with Peter until the opera house, where they jumped back. How did she get switched out? I'm assuming the Olivia in the cell that Walternate observes at the end is Olivia1, while Olivia2 traveled back with Peter and Walter... did I miss something? Or is PETER in on it??? The impression I got from the confrontation out front of the opera house was that Olivia2 was still with her unit, since she and her boss were sympatico. Can't September get here??? Come on, season 3!
Answer:
The Olivias got switched out when Olivia1 threw the grenade at the end. While Bell is unconscious, Olivia1 is taken away, and Olivia2 is the one who rouses Bell and then returns to our world.