Anyway, then Walter apologizes for what he's going to ask next: "On September the 11th, when the terrorists struck, which buildings did they attack?" The Pentagon, says Pratchet, and then: the White House. And then he dies. "I think I know what happened here," says Walter, but there are still more surprises in store before Walter can explain: specifically, a big lump moving underneath Pratchet's shirt. Walter unbuttons the shirt to find another Ted Pratchet head imbedded in Pratchet's torso. It opens its eyes, opens its mouth, gasps and goes silent as well. Walter closes Pratchet's eyes (both sets) and then says his theory was wrong: "This wasn't a quantum event at all. We're standing in two buildings, one of which comes from the alternate universe."
Sometime later -- it's daylight outside now -- Walter tells Olivia that he's asked to have Pratchet's body -- excuse me, bodies -- shipped back to the lab: "Maybe they'll provide some insight into how this thing happened." Olivia says she already knows how it happened. "Two universes colliding," she says, adding that William Bell warned her that Newton would try to open a doorway from our universe to the next, and this would be the consequence when that happened. "Two objects trying to occupy the same space at the same time," says Peter, who hasn't even had the benefit of Nina Sharp's snowglobe demonstration! "This was Newton. I'm sure of it. He was here," says Olivia.
Meanwhile, back at the Harvard lab, Astrid lifts the sheet covering Pratchet's bodies and discovers that she has a limit, and this is it: "I've seen some pretty disturbing things in my time working with you, and I think I've handled them pretty well, but this? I can't do." Walter agrees that it's awful, and suggests she look through the boxes of stuff from the building, looking for anything that might seem out of place, which Astrid happily agrees to do.
She starts pulling stuff out. "I think this qualifies: Richard Nixon on a silver dollar." "That's disturbing," jokes Walter. Astrid asks Walter how, when he separates the bodies, he'll know which one is which. Alternate universe Pratchet was married, so he'll be the one with the wedding ring on his finger, explains Walter, which is awfully presumptuous. What if the alternate universe marks marriage with genital piercing instead? Astrid says, "So as far as his wife will ever know, he just disappeared? That is so sad," she says. Walter agrees, and then Astrid finds a toy double-decker car in the box of effects. "Does this mean that they drive these over there?" she asks. I suppose so, says Walter, who pauses, thinking about something. Astrid asks him what's up. "I know what Newton did. And I'm afraid I've just remembered what's going to happen next," he says.