Doctor Who Series 10: 11 Easter Eggs & References In 'Oxygen'
6. The Doctor In Space
The Doctor gives Bill his space suit in order to help her survive the vacuum of space. He is then able to survive due to his Time Lord physiology. This fact was first established back in 1982's Four to Doomsday where, in a scientifically ludicrous sequence, the Doctor played a spot of cricket in space.
Bill isn't the first companion to be jettisoned out of a space station airlock. In 1965's The Daleks' Master Plan, Katarina became the first companion of the Doctor's to die when the same thing happened to her.
Visually, the way Bill's face frosts over as she is exposed to the vacuum resembles a similar scene in Guardians of the Galaxy. In that sequence, Star-Lord gives Gamora his helmet, just as the Doctor does for Bill here.