Plot hole: When interrogating Boone, Olivia shows him a photo of a body with the spine torn out in the woods. This body hasn't been found yet, as a later scene has Olivia and Peter go to the same location and find the body. You can tell it's the same body because the shirt is the same in both the picture and the crime scene.
Continuity mistake: At the club, when Peter and Olivia are looking for Valeria, Peter is wearing an ear piece in his left ear. When he talks to the woman, the piece is missing.
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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