Nurse (World Enough and Time)
From Tardis Wiki, the free Doctor Who reference
The nurse was a Mondasian and a descendant of the original skeleton crew of a Mondasian colony ship caught in the gravitational pull of a black hole. Because of the black hole's time dilation, the bottom of the ship had a much faster flow of time than the top of the ship.
The nurse was the surgeon's assistant. At some point they established Operation Exodus. It involved augmenting hospital patients by turning them into Cybermen so that they would survive the journey to the top of the ship. However, the process was extremely painful and to keep its nature a secret, the nurse would typically silence any patients who cried out in pain.
