And Those We Left Behind - S4-E6
Plot hole: The very ending scene where Peter (in this version died in the ice as a boy so Walter's wife never met him) takes off some of the dust covers then picks up a toy airplane. The toy airplane he got as a child from ... Walter's wife when she was trying to placate him in an earlier episode for trying to run "home". This toy airplane wouldn't have been his as a child in this version of the universe. (00:42:00)
And Those We Left Behind - S4-E6
Factual error: In the final scene with Peter and Olivia in Walter's campus housing, Peter uncovers items that should have been in the house for years and they are dusty. The last thing he uncovers is a brand new flat screen HDTV with stickers on it, which would not have existed 17 years prior to then, when he was committed to St Clarie's Institution. (00:42:10)
And Those We Left Behind - S4-E6
Continuity mistake: While beginning to take the radiation readings of the Jeep during his time jumps, Peter has a wedding ring on his finger. After cutting away and back again, the wedding ring is no longer on his finger. (00:15:15)
Answer: He helped his father evade capture, impeding the investigation.