After she gets off the phone, Astrid relays the news that Swift confessed, and that the monster had nothing to do with Walter's work. She tells them Swift was working with a guy named "Cameron Deglmann," and Walter's all, "Of course!" and explains that Deglmann was a pioneer in hybridization: "Quite brilliant. In fact, it was his work that inspired my research in the first place." And Peter's a little choked that it never occurred to Walter that this Deglmann guy might be involved, which Walter chalks up to the guy having a very forgettable face.
Oh, and Olivia was also able to get the combination of animals that went into the hybrid: Gila monster, a parasitic wasp, and a type of bat. "Of course! Why didn't I think of it before?" says Walter, and Peter knows where he's going with this, and the two of them explain to Astrid that the bat's immune system makes it a perfect candidate for hybridization. "They can carry hundreds of different diseases without ever being affected," says Peter, with Walter adding that that would enable the creature to mature without rejecting its various parts.
So Astrid wants to know if they can help Charlie now that they know what the animal's made of. I'd like to point out that before Walter and Peter interrupted her to go on their little bat tangent, it sounded like Astrid was about to list another ingredient in the genetic Zoodles creature, but I guess not. She suggests that they try baiting it in the sewers. Peter scoffs at the idea of going down into the sewers and waiting for the thing to eat them, but Walter thinks it's a great idea. Well, at least the going down into the sewers part of it, but not to bait it with food: "We do have something that it is interested in."
And Olivia' back by the time Walter's holding up the beaker of larvae and explaining that bats are a highly maternal species, quite protective of their young, so they're going to find a central location in the sewer to lure the thing, since bats are capable of seeking their offspring from miles away.
And since I'm by this point just outright ignoring Peter's constant sarcastic comments, I'll just say that Walter goes on to say that since he knows the biological makeup of this thing, he thinks he can kill it: "Assuming you can provide us with 50-calibre incendiary rounds, Agent Dunham." Yeah, how many animals could you not kill with 50-calibre incendiary rounds, Walter? Olivia gently tells him that that's not exactly FBI standard-issue. And is he sure about this? Yes, he's sure they can lure the thing. But he's not sure they can survive the encounter. He says the first part loud, and the second part quiet.