The ID number "2026" on the squad car in 'The Last Sam Weiss' foreshadows Peter's experiences in the year 2026 in 'The Day We Died'.
Painted text in a parking space in 'The Day We Died' says "ONLY SEPT". In 'Neither Here Nor There' Peter's fate is once again in September's hands as he's the only Observer who has any desire to prevent Peter from being fully erased.
WALTER: "It's a paradox. I can't change what happens because it's already happened, but, you can make a different choice within what happened. I simply need to find a way to bring your consciousness forward to now so that you can witness what will happen if you make the same choice. Peter, for all I know it could be happening already. Don't you see? We can fix everything! We can cheat the rules of time!"
PETER: "I understand now. I understand what the machine does. I know what it's capable of and I know where it came from."
WALTER: "The First People."
PETER: "Yes, the First People, Walter, but the First People are us. You, most specifically. And maybe Ella and Astrid, I don't know. I don't know who it was that took the machine back through time. But I know something else. I've seen doomsday and it is worse than anything you could possibly imagine. This isn't a war that can be won. Our two worlds are inextricable. If one side dies, we all die. So I've torn holes in both the universes and they lead here, to this room. A bridge so that we can begin to work together to fix-"
DECEMBER: "You were right. They don't remember Peter."
SEPTEMBER: "How could they? He never existed. He served his purpose."