“That’s the second batch,” he tells me. “You’ll see it full again by the end of the night.”

By 10:30, the dining room is more crowded than it has been all day. A party of eight Europeans crams into a table meant for six, right next to Trujillo. A manager, Robert Khimeche, watches them, arms crossed. “I must protect him,” he says, only sort of kidding. At around 11, as this surprise rush’s orders come in, the pass fills up with dishes, but none of the four food runners are present. This could prove disastrous, the sort of domino effect that a kitchen might not bounce back from: dishes could go out cold and come back for refires, clogging up the line for rest of the night, creating delays, angry customers, cuss words and — worse — comps. The sous chef paces, showing signs of stress. He walks out of the kitchen to yell, “Runners!” through the swinging doors. And sure enough, the machine kicks back into gear. The runners return from the floor, or wherever they had been, and the pass is emptied again in two minutes. A new stack of P.O.S. tickets hit the spike.

By the end of the day, the rotating staff of six cooks behind the line will have produced 111 steak frites, 90 French onion soups, 88 Balthazar bar steaks, 69 burgers, 68 omelets, 62 goat-cheese tarts, 56 chicken paillards, 51 chicken clubs, 48 seared salmon fillets, 46 heirloom-tomato salads, 45 sides of fries, 44 chicken-liver-and-foie-gras mousses, 43 duck confits, 40 grilled dorades, 39 steaks au poivre, 39 eggs Norwegian, 38 steak tartare appetizers (plus 16 entrees), 32 escargot, 32 moules frites, 29 grilled trout — the list, pulled from the P.O.S. terminals, goes on and on and on. The volume benefits the whole staff. Tonight, the waiters earn $345 in tips, the runners $207 and the busboys $172, which does not include the $5 an hour Balthazar pays them.

A little past midnight, the dining room is emptying out. Even the bar is empty, which is where the manager on duty sits down for a plate of duck confit. Shortly after, the waiters whose sections have emptied change out of their white shirts and aprons, and the waitresses ditch their French-maid outfits, and they gather to drink wine from unfinished bottles, raiding the kitchen for leftover prep. The night porters show up and start scrubbing the kitchen upstairs and hosing down the prep kitchen, where the veal stock still bubbles away.

The closing manager, Khimeche, traverses the restaurant’s catacombs carrying a key ring that would put an N.Y.C.H.A. superintendent to shame, dropping it a number of times as he rushes about, frantically locking everything up, placing cash in a safe with an obscenely noisy crank, running a few photocopies and then booting the waiters from a V.I.P. banquette before finally closing the doors. He steps outside at 2:30, as the waitstaff, having decided against going out for more drinks, disperses into cabs. In just a few hours, the delivery trucks will return and it will start all over again.