Expulsion of Skaro
In the Warrior's universe, the Expulsion of Skaro was the name used by the Warrior to refer to one of his numerous failed attempts to end the Time War.
During the War's final segment, when the Warrior was briefed by the White Guardian of his mission to assemble the Key to Time, the Warrior mentioned the Expulsion of Skaro, along with the Cascade Rush and his detonation of the Moment, as proof of his belief that ending the Time War had become fundamentally impossible, and thus assembling the Key to Time would also be a fruitless endeavour. (AUDIO: The Key To Key To Time)
Behind the scenes
It is unclear if the Expulsion of Skaro is intended to be a reference to the Carrisent Particum timelines of AUDIO: Aftershocks or not, as although the name "Expulsion of Skaro" is never directly linked to the Carrisent Particum timelines, the name of the event suggests that it involved Skaro being expelled or banished in some capacity, which is, to an extent, what occurs to the planet - or at least, multiple versions of Skaro - in the Carrisent Particum timelines of Aftershocks.