Chapter 3: Page 15: Line 17 (108)

 Mason has been shov'd about and borne along in riots of sailors attempting to wrest from bands of Medical Students the bodies of Shipmates come to grief ashore, too far from the safety of the Sea,— and he's had his Purse, as his Person, assaulted by Agents public and private,— yet, "There's nothing like it, it's London at its purest," he cries.

* * * * * * * * * *

Line 108 Vulgarized:
The place is always complete chaos. Mason is often stolen from and physically shoved about, by both the law and commoners. He's been caught up in mobs of people fighting over the deceased body, one side always medical students looking for another corpse to dissect, the other either shipmates of the hanged, or Christians trying to keep the body intact for the day of the Lord's judgment and resurrection. Despite of, or perhaps exactly because of, these things, Mason loves it and finds solace in the event, a microcosm of his London home.

Subtext:
I suppose Mason loves London more than I speculated earlier. I felt maybe he'd be uncomfortable in it but apparently he gains comfort from the utter chaos and close proximity of so many others. Perhaps what he is uncomfortable with is being in is his own skin, so he needs the outside stimulus to pull himself out of his own head. He needs the chaos to keep from diving too deeply into his inner self. The public hangings, the death, is the lure for him but once there, he feels comforted by the overwhelming sensory input provided by the crowd.
    Later we'll learn that Mason spent the entire week lost to the change in calendars by himself in some dark otherworldly space while everybody else simply chugged along as if nothing had happened. Perhaps that experience, the fear and the loneliness of that week, has caused him to embrace being around so many others. If he is in close contact with others, no matter how chaotic or violent, it means, maybe, that he won't slip away into a world of his own, and possibly lost there for eternity.
    Whatever the case, Mason either really loves London or he really loves public hangings!