Nuns with guns shoot up the North End

Mary Pierce posts video of gun-toting nuns at Commercial Street and Foster Street as part of, naturally, Ben Affleck's roving art installation, Guns on the streets of Boston. Actually, it looks a lot like a lot of people milling around not doing anything much besides shooting guns, then the nuns show up, then everybody goes back to milling about, firing weapons.

Oops, did I just give the plot away?