When filming “ The Pitt ,” a number of things must go exactly right; the medical drama’s 360-degree hospital set and painstakingly produced prosthetics leave little room for error. So for Season 2, creator R. Scott Gemmill upped the ante by introducing the most unpredictable element of all: a baby. More than 12 adorably swaddled infants played the abandoned newborn Baby Jane Doe over the seven-month shoot, including 4-month-old twins Luca and Luna; Luca can be spotted nestled on the shoulder of Dr. Robby (Noah Wyle) in the finale’s concluding scene, an overdue moment of catharsis for the anguished attending physician. “They really needed a sleeping baby,” says their mom, Desanka Pinder. “Lucky for him, he just happened to be tired.”  Safe to say, Luca has bragging rights for life — how many babies can say they’ve shared the screen with an Emmy-winning star?…