The raison d'être of this cheery, 52-year-old basement bistro is to get theater-going patrons fed and out the door by curtain time. Perhaps it was the staff"s preoccupation with speed that led to an erratic meal. The traditional soups were sound (cold potato, onion), as were firm, buttery snails. Boeuf bourguignon was a winey charmer, perfect for a cold night and a better choice than the rather dry, sticky-sweet duck á l"orange. Frites were forgettable, and the chocolate mousse was as dense as toothpaste, so even if you don"t have a curtain to catch, it"s best to end your meal after the entrée.