This episode's glyphs spell:
The Observer can be seen at the park where Fauxlivia walked around with Henry.
A poster in Olivia's mind in 'Lysergic Acid Diethylamide' that says "Be Vortex Aware" foreshadows the vortex that consumed part of a ranch in '6:02 AM EST'.
The lightning bolt bumper sticker on the rancher's truck in '6:02 AM EST' foreshadows the widespread lightning attacks in 'The Last Sam Weiss'.
Similar phenomena started happening in "6:02 AM EST". (Image 1)
Walter got angry in "Peter" when Carla Warren spoke that same Oppenheimer line at him.
The Observer was orchestrating a plan to test Walter. At the end of the episode he discussed the event with December.
In '6:02 AM EST', as Walter struggled with the idea of allowing Peter to enter The Machine, he recalled the words of the Observer.
Sam Weiss told her that in "Concentrate and Ask Again".
A radio broadcast from the Redverse in "6:02 AM EST" mentioned the Dodgers playing at Ebbets field in Brooklyn.
In "The Boy Must Live" Walter told Peter about memories he regained from the original timeline, including memories of Peter stepping into The Machine from "6:02 AM EST".