When Dr. Crenshaw is preparing to operate on the elderly patient he has taken from the ER, the nurse putting on his gloves fails to put his left glove on properly - his fingers don't go into the gloves' fingers. The actor briefly tries to fix it but can't (without being seen by the camera), so he keeps his hand at his side throughout the scene. When he moves to the patient's side and takes the scalpel (with his right hand) to begin operating, you can see his left hand never enters the frame to keep the problem hidden.
When Abby is singing on the phone in the trauma room, the heart monitor on the side of the frame is still displaying a rhythm and heart rate, even though the patient has already been wheeled out of the room.