Peter's telling his dad that there has to be something he can do, but Walter looks awfully despondent. "You can't check out right now. We cannot let this man die!" His dad snaps that he knows that, loudly enough that Astrid, Olivia and Charlie look over to see what the commotion is. Walter says he's thinking, and then he looks over at a beaker with a couple dozen writhing larvae. He tells Astrid to draw 25 milliliters of blood, and tells Peter to get some trichlorimide; he's going to try poisoning them.
Astrid warns Charlie that the needle is going to pinch a little bit, and Charlie grimaces, like you'd think it would take a lot more than this to cause him pain, considering what he's just been through. While Peter and Walter prepare the poison, Charlie asks how much time he has if this doesn't work. Olivia says, "The last victim, we figured 24 hours after he was..." "...knocked up," finishes Charlie. Olivia says yes. "So I have about 16 hours," says Charlie. Well, I have an idea! Someone pull up a television and a couple seasons of Arrested Development, and the time will fly by!
We head over to a park now, where a woman shows up with her young son, who goes off to play on the equipment while his mom sits on the park bench to yap on her cell phone. As the boy runs around, we see a huge tail, with spines and a rattle at the end of it is pulled into one of the large pipes for kids to crawl through. Nobody's seen this yet? Still, let this be a lesson to people who talk on their cellphones instead of watching their kids: your kid might get eaten!
Over at the federal building, Broyles tells Olivia he's made a few calls for her and got the army to declassify some information on Kelvin Genetics, which had five lab assistants who worked with Walter and William Bell, all of whom are now in the private sector, none working in biogenetics, as far as he can tell. And he couldn't find a connection to Robert Swift. Olivia's still hung up about finding the fourth activist: "And if they're out there and impregnated, then who knows how many more of these things we're looking at?" she says, although Broyles points out they'd presumably have heard something by now. He asks if there've been any more sightings, and Olivia says, "Not within the last ten hours," and Broyles wonders if maybe it's gone: "Maybe it went into the river or died from lack of proper food," he says, like the Fringe team should be so lucky.
A desk agent tells Olivia that Peter's on line two, and she picks up and he tells her he's got bad news: "The poison killed the larvae, but it also poisoned Charlie's blood." Well, it's poison, Peter. It was kind of a dumb plan. Olivia asks how Charlie's doing, and Peter says he's putting on a brave face, but he's not doing well; his blood pressure's down and his kidneys are failing, which Olivia doesn't understand, and Peter explains that the larvae seem to be acting as parasites, feeding on their hosts for nutrients. Well, sure. Human larvae (i.e. fetuses) do that, you dingbats.