What might be the ethical and legal reasons for the nurse to refuse to follow the physician’s orders?

A 5-day-old premature baby was believed to require a blood transfusion because of increasing anemia. The parents were Jehovah’s Witnesses and did not wish to have blood or blood products given to the baby. A court order was obtained with the parents’
knowledge, and the blood was given. The physician on call the next night did not think he needed to obtain the court’s consent for an additional blood transfusion because it had been granted for the earlier transfusion. The blood was ordered, and the nurse was asked to administer the blood. The nurse refused for ethical and legal reasons.