Place pork tenderloins on plate, and rub with 1 tablespoon oil, the salt and pepper. Heat ovenproof 12-inch skillet (not nonstick) over medium-high heat until very hot. Add both pieces of pork, and brown 2 minutes, then turn and brown on second side for another 2 minutes. Brown on third side 2 minutes longer, then pour sauce mixture over pork; immediately transfer to oven. Bake 5 minutes; pour vinegar over pork. Bake 25 to 30 minutes longer or until pork is cooked through and can easily be pulled apart with fork.