Katherine travels into the steamy Gut of London to find the engineer who witnessed Hester's fall. She's trying to find Nimmo.
Gut Supervisor Nimmo leads her through Section 60, where they're turning London's human waste (yes, that kind of waste) into edible bars. We hope they have some genius marketers. We can't imagine anyone saying, "Man, I've got to get me one of those Number Two Bars."
Anyway, Katherine witnesses how they treat slackers down in the Gut: they taze them. Ouch. Before the poor guy can shout "don't taze me, bro," he gets dragged off to K Division. What happens there? Human body parts get made into Special K?
Finally, Katherine gets to talk to the engineer Bevis Pod, but he won't tell her anything she doesn't already know.
She vows to get her father to help improve working conditions before she leaves. Yeah, because he's totally a guy who values human life.