Back at the lab, the body of the dead woman is arriving, but Walter has disappeared. In this universe, Walter is too scared to leave the lab, so they figure he's gotta be around somewhere; Astrid goes to check the bathroom while Olivia checks Gene's stall. As soon as they're out of the room, Lee hears some noise coming from the good ol' isolation tank, and then a scared, drenched Walter flings open the door. "Is it safe to come out? Is he gone?" he asks, but Lee has no idea who this man is that Walter is freaked out about. "There was a man in the mirror! And when I turned around, he wasn't there," says a very agitated Walter, who only calms down after Astrid and Olivia rush back, Olivia soothingly telling him that whatever it was, everybody's all there now and Walter's OK.
Astrid goes to get Walter some dry clothes (while Walter strips down naked right there in the lab), and Lee and Olivia have a hushed definition over whether Walter's all right or not. "Well, that depends on your definition of 'all right,'" says Olivia. My definition usually means there isn't a need for a qualifier like that, actually. Olivia says Walter is functional, except when he's not. "But he is often quite brilliant. He just never had anything to tether him to the world," she says. You know, like a grown son who was recently erased from existence.
Walter, dressed only in a towel, notes the engagement ring on the woman's hand and calls it sad. "I don't think there's anything sadder than when two people are meant to be together and something intervenes," he says, and if you'll excuse me, I have to go put some ice on my head for the bump that just rose up after the script hit me in the head.
And then Walter gets spooked by the noise of one of those old-school ribbon printers, and Astrid tells him it's just the test results he wanted: turns out that the victims don't all suffer from iron-related diseases -- which was Lee's suggestion and which Walter calls, "clever, but wrong," and which Lee calls a long shot. But all is not lost, because they all suffer from health problems -- gout, hair loss, kidney diseases -- which were all caused by some form of heavy metal poisoning: lead, zinc mercury. How about absentminded-professor-itis? Because Walter is only just now realizing that he's not wearing any pants. (Astrid goes to fetch him some.) The sheer number of victims indicates this can't be a coincidence (the poisoning, not the, uh, pantslessness) but the levels of metals in the victims' blood have returned to normal, suggesting he's taking particles from their blood. And we're only halfway through the show, so Walter's not going to have a hypothesis on this yet.