You know the city pretty well, so you drive somewhere secluded (but ideally not too far away) where you feel fairly secure that you can fire a gun and not be seen or heard.
Where do you go? I assume there are probably warehouses related to shipping that would be deserted at night (maybe around the Brooklyn Navy Yard??) but I am pretty ignorant about this sort of thing and certainly don't know where the most isolated place would be.
Searches: tried vague googling of "Brooklyn warehouses," "Manhattan warehouses," but I'm not really sure how to search for this.