Opening an Airlock door to space without the Player's Ship attached will vent all hostiles, items and drones in that room into space.
If there are any open doors in the room exposed to space, the adjoining rooms will also be progressively vented.
Venting is quite fast although with quick reactions it is possible to move drones between rooms towards airlocks without venting them.
A room will flood with Radiation when exposed to space for extended periods.