This entire section of the chapter (from the page revealing the Lodgers up until about next week's page) was really rough to write!! There's like at least versions different versions of Brokenshire trying to push Jekyll into a corner, and it wasn't until very late that I stumbled upon the (probably obvious) idea that he could use bureaucracy--in all its inefficient glory--against him.
Before that was an idea (one I would still like to keep as canon, for anyone reading these comments) that Brokenshire had been the one to investigate Moreau when he first started delving into dangerous scientific territory. Moreau had once been a gentleman scientist of great renown--up until the day Brokenshire walked into his laboratory and discovered the depraved experiments within. Brokenshire recounts this story to Jekyll both as a cautionary tale and a lowkey threat: he's not falling for Jekyll's gentlemanly facade anymore. He's seen what it can lead to.