Anyone who's ever read Mark Kurlansky's The Big Oyster: History on the Half Shell is well aware that early New Yorkers once gorged on oysters by the several-dozen at markets, in oyster saloons, stalls, shanties, and pretty much every filthy 19th-century nook of lower Manhattan we'll invariably have to compare to some tavern in Gangs of New York if this sentence goes on any longer. This guy, in any event, seems to be taking the revival of all that a little too far, with his shucking knife, raw bar, and condiments on the N train. It doesn't seem to be performance art, either.
Update: It was a prank, or something; the subway shucker is a BuzzFeed employee who reportedly enjoys "good ol' internet fun." In other words, it's unclear if he actually enjoys oysters.