They go inside, guns drawn, but the place is devoid of life. The walls are covered with equations, though, so they know they're in the right place. Peter, meanwhile, has found a wall with a framed newspaper story that reveals Neil was a twin. His brother and father were killed in a car accident. The wall is festooned with pictures of people like Jesus, Gandhi, Joan of Arc. "What's the connection? They're heroes?" he asks. Olivia's figured it out but instead of just saying so, she asks Peter what else they have in common, and then answers for him: "They're all saviors."
There's no sign of Neil, though, but a picture that Olivia got from the mantel may hold the answer: it's a picture of Neil with an older Asian woman. Great job! Now you know Neil has a mom!
And Neil is at his mom's house. There's a safe in which he's storing the glowing blue stick, and he pulls something out that's wrapped loosely in a cloth. It's a .45. He puts a clip in and jacks one into the chamber. Then, tucking the gun into his waistband behind his back, he strolls out into a living room where the older woman from the photo says, "Where are you going? I don't understand. What do you mean, you are here to say goodbye?"
When we get back from commercial, Neil's mom asks him again, and he says he already told her. "'Where I belong' is not an answer," she says. Ah, it's the battle hymn of the Tiger Mother! She asks if he got fired again, and he says that he wasn't fired from MIT; he left.
He's staring at her intently at this point, enough so that she finally says, "What?" and he tells her that he heard her the night Alex died. "You said God took the wrong one. 'Why did God take my angel?' you kept saying." Yeah, it's not a fun speech. He accuses her of resenting the fact he wasn't Alex, and he was afraid that he would never be good enough. It's no coincidence that this mirrors (no pun intended) the Farnsworthbot's worry that her father would have loved her more if she were like her own other-universe twin. But guess what! God had a plan. Oh, doesn't he always? Neil says that God let him live for a reason, and gave him a way to see the future. To prove it, he does the say-everything-the-other-person-says-at-the-same-time thing, and his mom's really starting to get freaked out. She apologizes and then, almost amusingly, says that he never should have heard what he did that night, which is not exactly the same thing as admitting she never should have said it.