Peter goes racing upstairs, because somehow he knows that the light is projecting through the ceiling without burning a hole in the floor. Good thing he does, too, because standing there in the beam of light is September. "Thank you," he says, as the light vanishes and he's left standing there on the floor (I guess it would have been tricky to deposit him on the tip of the bullet). Peter asks what September is thanking him for, and September says, "They hid the universe from me. They locked me out." Now, September, I think maybe you could try a little harder at work too. "What I led you to, is a beacon. I needed you to activate it, so I could find my way back," he says.
Peter's all, "So I helped you." He looks kind of pissed. Clearly he's thinking, "Suuure, when an Observer needs to find his way back, all you have to do is turn on a cosmic flashlight, but still I'm stuck here." At any rate, he wants September to help him now, because he's tried everything. "And nobody here can help me, but you can. I know you can." Peter says "please" and everything!
September cocks his head, displaying about as much confusion as it's possible for any Observer to show. "You have been home all along," he says. Peter doesn't understand, what with him having been erased and all. "There is no scientific explanation," says September, in a colossal understatement, "but I have a theory: Based on a uniquely [sic] human principle, I believe you could not be fully erased because the people who care about you would not let you go. And you would not let them go."
And then September says -- groan -- "I believe you call it 'love,'" like he's some sort of robot from another universe instead of someone who can observe all of humanity across history at once and yet still somehow not be sure if "love" is this thing that humans share, for GOD'S sake.
And Olivia? asks Peter. "She is your, I believe you call her 'Olivia,'" says September. Okay he didn't really say it like that, but that's how I'm going to make him talk from now on.
Then the house starts to shake and September puts on his hat. Peter runs for cover and September disappears and there is a big crashing sound and when Peter gets downstairs, there's a big hole in the floor where the beacon used to be, but if he puts a big throw rug over it, I'm sure it will be fine. It doesn't even seem to bother him; he's got half a smile on his face.
There's Olivia, getting out of her car because either she's home or she forgot to plug it in. And there's Peter, waiting for her. She stops, and he starts to walk toward her, smiling and she starts hustling her skinny ass over and then they hug and spin around, and then they -- I believe it's called a "kiss."