After responding to a commercial aviation disaster in rural Vermont, Peter, Olivia, and Walter wander into a nearby town that doesn't seem to have any way to leave. The general population is either dead or deranged and the Fringe investigators have to fight their way to sanctuary before the area is 'erased'.
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Olivia started to regain her memories from the original timeline in this episode, and the name Olive, her old nickname, hints at this reversion.
The Observer can be seen standing with the stranded motorists watching the plane fall out of the sky.
The sign for "Quimby Ale" outside of the liquor store in 'Making Angels' foreshadows the importance of the shop at the corner of Cyprus and Quimby in 'Welcome to Westfield'.
The "Killer Bees" mascot name on the high school exterior in 'Welcome to Westfield' foreshadows the hive-mind abilities of the villains in 'A Better Human Being'.
As Olivia started remembering things from the original timeline in "Welcome to Westfield" she mentioned the case in Edina from "Johari Window".