Olivia and Jessica part ways as they arrive at the police car that's going to take Jessica home, so she tells Olivia, "If you ever need help getting to the head of the line in an ER..." and Olivia lets that stunning indictment of the U.S. health-care system pass but tells Jessica to call them if she gets any more symptoms and Jessica says she will.
No sooner is Jessica in the car when Olivia's cellphone rings. It's Broyles, who doesn't even say hello -- rude -- but tells her they know who's responsible for the nanites.
And now they're back at Fringe watching surveillance footage of the John McClane Center and they see that ten minutes before the first victim was reported, David Robert Jones was tampering with the escalator. I'm sorry, but how long could it have possibly taken to check the security footage? Why did it take them this long to find out? Anyway, Peter's looking on the bright side: "At least we know Jones is in our universe." Actually, that's a pretty terrible bright side.
Olivia's pretty bummed and wonders why Jones is poisoning a bunch of people with nanites. "Everything Jones has done has been in service of collapsing our two universes in order to create a third," she points out and Broyles reminds her that destroying the bridge ruined that plan. "As far as we know," she says -- yeah, did you guys all assume that he would just give up? Apparently, yes; yes, you did.
Back at the lab, Walter's examining the nanites and is shocked to discover chimeric structure, whatever that is. Astrid comes in with the news that David Robert Jones is behind this, but Walter's too gobsmacked by chimeric structure to respond. "A hundred different ways to design a nanite and he chose this. It's inconceivable, not by chance. Jones isn't smart enough, not by himself." I keep enjoying Walter's on-again, off-again "Jones is an idiot"/"Jones is brilliant" routine. Anyway, he says Jones didn't design these nanites and there's only one person who would construct this particular design. Astrid asks who. Walter doesn't answer...
... but we're going to get the answer now. Jones is aboard from, by the sounds of it, some kind of ship and he enters some sort of office (and composes himself to do so). Addressing the man standing behind a desk with his back to Jones, Jones says that he has bad news and addresses the man as "sir": "Agent Dunham has stopped us again." So we're left to quickly try to figure out who this could possibly be -- who would be important enough to warrant the dramatic reveal and be someone who David Robert Jones reports to and it wasn't that difficult to figure out it was Bell, right before he croaks out a chuckle, turns around and says, "Don't be so sure."