"We've been trapped here for days. Our whole damn town's destroyed. Our friends, our families, everyone's going crazy, and the U.S. government sends three people?" he snaps. Well, budget cuts, you know. Better to send three FBI agents than curse the darkness!
Olivia promises that help will come, but in the meantime they need to work together to figure out what's going on and how to get out. That's where Walter comes in, saying that if has a chance to examine one of the victims, they may be able to get some answers.
Fortunately, there's Teresa, locked in the classroom. Walter shines a light in her (normal) eyes. She seems a little spaced out, and when Walter snaps her fingers, she says, "You're the man from the government. You're here about our air quality. The air quality's bad here, isn't it?"
Walter checks her mouth, and finds a double row of teeth in her lower jaw. "Fascinating," he says, as Angela -- Cliff's wife -- gasps. Walter's got a theory now, which he shares with Olivia, after telling her about the double irises of the diner's cook: "Perhaps whatever is afflicting these people is creating some sort of rapid mitosis, causing the cells to replicate exponentially, duplicating body parts," he says. Man, what I could do with four arms! Or two p-- anyway, Walter goes back to examining Teresa, who flops a hand against his chest and says she should go start supper, since Lee will be home soon. Angela points out for Walter and Olivia's benefit that Teresa's husband died six or seven years ago, and so Walter, taking a blood sample, asks Teresa herself when the last time she saw Lee was, and she says it was this morning, when she packed his lunch before he went to work. Walter, I assume just making conversation while he draws the blood, asks what she and Lee talked about, and she turns suddenly, snapping and asking if this is some kind of sick joke: "My Lee's dead. Seven years this April." Then, a moment later, she's dreamily spacey again, saying she should start supper, what with Lee going to be home soon and all.
Peter strolls in, having been unsuccessful at getting the radio to work. "I couldn't get a signal. Even if I had a generator twice that size, there's just too much electromagnetic interference." He thinks they're stuck there for a while. Olivia tells him about Teresa thinking her dead husband is still alive, and Peter urges her to let Walter test her blood too.
She stares at him for a long while, and then we cut to Walter taking a blood sample while assuring Olivia that the symptoms she's feeling are probably just psychosomatic: "You were always very empathetic, even as a child. That's why you're such a great investigator: your ability to empathize with the victims," he says. Of course, that doesn't explain how she had a memory of a case that Peter worked with another Olivia, but maybe Walter's forgotten about that. At any rate, if they find out that it's not actually all in her head, then they'll just deal with it.