The extracting room was a facility contained within the Mire spaceship. It was used by the Mire to extract the adrenalin and testosterone from warriors around the galaxy, for sustenance. The chamber used electricity to liquefy its occupants. Adjacent to the extaction room was a storage container, where victims of the Mire were held prior to their death. The container had a rear wall which could compress mechanically, forcing occupants out into the extracting room.
When the Mire brought the warriors of a 9th century Viking village aboard their ship, they were stored in the container, and shortly afterwards killed in the extracting room. (TV: The Girl Who Died)