Richard and Caroline have their goodbyes with Michael while the team watches from a respectful distance. They tell him things that we don't hear, but can guess at. They wrap him up in a warm coat and cry and Michael wipes a tear from his mother's cheek. The Samuel Barber-like string music scoring this scene is just damned near killing me. Michael takes Olivia's hand and walks away from his home of the last 20 years.
Later, after Michael's gotten settled into his new bed at Formerly Harvard University, Olivia and Peter bring him a mug of hot cocoa. He probably can't taste it at all, but it's a sweet gesture. There are some moments when he's looking down at his mug when he looks uncannily like September. Perhaps he's a brother, a clone, a younger version... Didn't Walter refer to September as "Gemini" on another trip? Olivia sort of lies down at the foot of the bed, propped up on one elbow. Michael just keeps staring at his cocoa without drinking it. "I had a daughter," Olivia begins, "and when she was little, she loved hot cocoa. She used to say that of all the hot cocoa in the world, mine was her favorite." That gets Michael to try a sip, after which he rewards her with something approaching a smile. "Do you know me?" Olivia asks. "Do you remember me?" There's a long pause and then he nods, once. For some reason, Olivia has to explain to Peter that Observers experience time differently, and that's how the boy can remember them even though they met in another timeline. Then Peter's like, "Oh, hey, that reminds me I need to change my bandage from where I cut myself because I was almost an Observer myself."
Walter is off in his lab, still on his acid trip. He sits on the floor, slumped against a cabinet while scenes from his past play out around him. Everything in the lab -- including himself at certain points -- becomes an impromptu screen upon which images are projected. First he remembers comparing himself to God. Then he remembers arguing with his wife, pleading with her to believe in him. He remembers Peter dying, and then creating the portal into the other universe over Carla's protestations. Nina tries to stop him, too, but he ignores her. "There has to be a line we can't cross," Carla says in the projected memory. Walter disagrees: "My son is dying, Dr. Warren. I will not allow that to happen again." Carla quotes Oppenheimer quoting the Bhagavad Gita. "Now I am become death, destroyer of worlds." Walter remembers Peter -- his stolen son -- drowning in the icy lake because in this timeline, September wasn't there to save him. The image of Peter floating in the dark green-blue of the water projected across Walter's defeated from is hauntingly lovely.