So they're back at the Harvard lab. Broyles tracked the postal code, and they've discovered that the package was sent from Chelsea two days ago, and Olivia is just downloading the post office security footage. Olivia explains all this to Peter as he strolls in, placing a coffee cup by Olivia's computer, very prominently in the foreground in a "this is going to be a plot point" kind of way. Olivia starts looking through the footage, and absentmindedly takes a sip of the coffee, then pauses and subtly looks at the cup. There's an X in the milk check box on the side. Oh, good! I was worried we were all done with the complaining about Fauxlivia this episode.

Meanwhile, Walter's got the doll in one of those airtight containers that you stick your arms in through holes in the side -- I don't know what they're called. While Astrid reads a bio of Blake -- a doctor who vaccinated thousands in underdeveloped countries -- Walter is spraying blue powder on a gnawed-on chicken bone, which starts to disintegrate. "How many times are you gonna test that? Or is this just a way for you to break your diet?" Astrid says, and Walter tries to pretend that he doesn't enjoy eating greasy fried food instead of telling Astrid to mind her own goddamn business. He says if he can figure out exactly what the substance is, then they may be able to figure out where it came from, and then he shows her a computer model of the molecule, and says a whole lot of fanciful blah blah blah about how the powder's molecules are capsulized, which preserves the agent until it's delivered into the host, and then it strikes him that he and Bell used a similar technique in the '70s when they were using their powers only for good and trying to find a way to vaccinate people without their knowledge. Walter says they discontinued the project when "Tricky Dicky" tried to use their research to develop biological weapons. Astrid is stunned by yet another one of Walter's breezily offhand revelations, and then floored when Walter says Nixon's wife kept coming on to him.

Walter's too busy ripping into the back of the doll, which I'm kind of surprised hasn't been done already. "Now, little lady, let's see what makes you tick. Because if I'm right, this is not some rogue's creation at all."