Hydra Combination

Hydra Combination was the material which comprised the door to at least the observation deck on the Game Station during the Dalek invasion of Earth in the year 200,100. Jack Harkness told Lynda Moss that it "should" keep the Daleks out, and the Ninth Doctor assured her that it was reinforced against meteors. Despite this, a Dalek armed with a blowtorch manipulator arm was able to slowly break through the door. However, this was rendered moot as, before the Daleks inside could break in, one of a group of Daleks from the outside instantly destroyed the glass window with a gunstick blast, killing Lynda as she was exposed to the vacuum of space. (TV: The Parting of the Ways)