Factual error: When the 747-aircraft of the fake German airline is being shown, you can see the German flag on the plane. But you also see an "N-xxxxx" registration which stands for USA. If it were a real German plane, it would have a "D-xxxx" registration.
Factual error: An aerial view of the "Miami Tower" (in Miami, Florida, of course) is labeled as "Boston Federal Building".
Factual error: When Walter removes the glass disk from Bowman's hand, he asks for a forcep, but is given a hemostat, which he uses to pull out the disk. My mother is a doctor, and when she saw this scene, she burst out laughing.
Answer: In the time line of Season 4, William Bell is trying to destroy both universes to create a new one, and he needs Olivia to power the collapse. So he helped her escape. But the real question is, if not in search of Peter, why Olivia has to travel to the alternate universe to be captured and replaced?
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