The various fringe events in this two-part season finale were engineered to bring out the strongest aspects of Olivia's powers for William Bell to use.
The Observer
The Observer can be seen behind the ambulance prior to Walter and Astrid being given access to the crime scene.
Timestamp: 04:29
Episode Clues
Previous Episode Clue
A sign for "Liberty Wind Chimes" in 'Worlds Apart' contains the Liberty Bell in its logo, hinting at the return of William Bell in 'Brave New World' (Part 1)'.
Timestamp: 31:05
Next Episode Clue
Signage saying "Eden" on the exterior of Bell's waterfront warehouse in 'Brave New World (Part 1)' foreshadows his mission to create a new, pristine universe with new creatures in 'Brave New World (Part 2)'.
Timestamp: 38:41
Items of Interest
Jones is working with Bell, who is alive. (Image 1)
The new mental institution administrator, Dr. Benlo, was played by John Noble's daughter. Benlo is an anagram for Noble.
Walter called Astrid 'Athos' and 'Alex'.
Image 1: Jones and Bell Timestamp: 19:16
Walter's Food
Walter made a lemon cake for an experiment and recognized the taste of Chilean almond oil.
A visualization of all the ways this episode connects to other episodes. Scroll down to see the actual connections.
Episode Connections
S1E01 - Pilot
In 'Brave New World (Part 1)' Walter sat in his old cell at St. Claire's from 'Pilot'.
Walter at his old desk S4E21 - Brave New World (Part 1) Timestamp: 22:07
S1E17 - Bad Dreams
In 'Brave New World (Part 1)' Olivia made the officers on the rooftop throw down their guns when she threw hers down, and she controlled Peter's movements as he fought Jones, just like Nick Lane could control others with his empathic transfer ability in' Bad Dreams'.
S1E20 - There's More Than One of Everything
Nina said that Bell was a father figure to Jones in 'There's More Than One of Everything'. They finally worked together in 'Brave New World (Part 1)'.
Jones got 'electrocuted in half' after fighting Peter in 'Brave New World (Part 1)' similar to how he got sliced in half in 'There's More Than One of Everything'.
Jones working with Bell S4E21 - Brave New World (Part 1) Timestamp: 20:17Jones sliced in half S1E20 - There's More Than One of Everything Timestamp: 38:53Jones electrocuted in half S4E21 - Brave New World (Part 1) Timestamp: 38:26
S2E04 - Momentum Deferred
Bell was unwell and needed oxygen in Olivia's memories in 'Momentum Deferred' which could be because he had lymphoma as Nina revealed in the alternate timeline in 'Brave New World (Part 1)'.
Bell taking oxygen S2E04 - Momentum Deferred Timestamp: 26:06
S3E19 - Lysergic Acid Diethylamide
The nanites in 'Brave New World (Part 1)' have an "X" on them that matches the "X" on the shirt worn by the man Peter freed from Olivia's mind in 'Lysergic Acid Diethylamide', suggesting that "Mr. X" from Olivia's mind may have been William Bell (who was ultimately behind the nanites).
Mr. X S3E19 - Lysergic Acid Diethylamide Timestamp: 27:14Nanites with 'X' S4E21 - Brave New World (Part 1) Timestamp: 17:26
S4E20 - Worlds Apart
WALTER about David Robert Jones in 'Worlds Apart': "This man... I'm afraid I underestimated him. Jones must have a remarkable mind to have devised a plan like this."
In 'Brave New World (Part 1)' Walter learned that William Bell was really behind everything.
Walter and Bell S4E21 - Brave New World (Part 1) Timestamp: 42:13
Spoilers for future episodes below!
S4E22 - Brave New World (Part 2)
WILLIAM BELL to David Robert Jones in 'Brave New World (Part 1)': "The art of chess, the art, is knowing when a piece is most valuable, and then, in that very moment, being willing to sacrifice it."
Walter sacrificed Olivia, the most valuable piece in the game, in order to save the world in 'Brave New World (Part 2)'.