There are two types of New Yorkers, the Underground Gourmet has always thought. There are those for whom eating a street-vendor hot dog (a.k.a. dirty-water dog) is an urban rite of passage, not to mention a show of defiance in this age of culinary correctness. And then there are those for whom it is an indication of mental incapacity, a deviant act that should best be left to ne'er-do-wells and unsuspecting tourists or healthy adults caught up in an emergency situation — like being locked overnight in a bank vault with a cache of Sabretts. Jeremy Spector, the chef of Employees Only, falls into the latter camp.