Airlock

An airlock is a device which permits the passage of objects, people, and the like, between a pressure vessel and its surrounding space while minimizing the change of pressure—and loss of air—in the vessel. The lock consists of two airtight doors in series which do not open simultaneously.

References

• The Drahvin leader Maaga tried to kill Steven Taylor by leaving him in a depressurised airlock ("Galaxy 4").
• To prevent Kirksen from blackmailing the Doctor into returning the ship to Kembel, and the Daleks, Katarina sacrificed herself by opening the airlock door on Mavic Chen's spaceship, 'Spar', expelling both herself and Kirksen into the vacuum of space and killing them both almost instantly ("The Daleks' Master Plan").