Rats, however? Probably fair game. Walter's pumping toxin into a glass case filled with the vermin, hoping to kill only the white ones. "I thought you were trying to block the toxin," says Peter, and Walter says he has to replicate it before he can figure out how to stop it.

Olivia comes in and says Astrid couldn't find any companies that purchased chromium trioxide within the past six months, but their EPA contact suggested they search for sodium chromate. "Of course. It's a sister compound. You treat it with sulphuric acid, you get chromium trioxide," says Walter, kind of grumpily, like Olivia's an idiot. Might I suggest that if that were so obvious, either one of those fabulous Bishop boys could have let Olivia know other compounds to search for as well? Anyway, Olivia found three local buyers, and gives Walter the list to look at. Two he identifies as pharmaceutical companies, and those ones are dismissed right off, because people who work for pharmaceutical companies obviously could never do anything bad, I guess, and Walter says he's never heard of the third. By this we can take to mean that he kept up his subscription to Pharmaceutical Startups Monthly even while he was in St. Claire's.

Peter looks at the shipping address for Hoffman Biological: 3340 Eastham Road, and points out it's a residential address. Olivia gets out her cellphone to tell Broyles she thinks they have a location.

Meanwhile, the Nazi is still listening to classical music. On a very old-looking record player, no less. He must be as excited at the resurgence of vinyl as I am. Or at least I would be, if I didn't get a frigging email every day from Amazon telling me that some album I already own is now on 180-gram vinyl, because they must know that I CAN'T HELP MYSELF. Let's call this guy Hoffman: he's putting together some sort of identification, which we'll presume is fake, given that I don't think too many IDs are handmade these days.

Meanwhile, the FBI descends on Hoffman's address. I always love the FBI raid scenes, all guns and bulletproof vests, gas masks ... and there are Walter and Peter tooting along, no armour, no guns. Hoffman can hear the footsteps of the agents pounding the floors up above as he works in his basement lab, but he doesn't appear too concerned. He certainly doesn't move with any more urgency. As Olivia gets the air-quality all-clear from an "Agent Doble," Hoffman gathers up a box of his Sterno candles, and turns up the heat on a burner underneath a beaker of purple liquid.