After escaping after being captured by the Time Lords, the Eleven took Helen Sinclair and hijacked a lone Battle TARDIS which he planned to use to stop the Eighth Doctor's attempt to stop the Doom Coalition.
Calera, upon discovering how much Padrac had ruined and manipulated her life, gave Helen some of her powers as the Sonomancer, and Helen was able to fight against the Eleven and hold him down. She was even able to resist a direct blast from the Eleven's weapon.
Helen used the Battle TARDIS to destroy the Resonance Engine, saving the universe. (AUDIO: Stop the Clock)
The Battle TARDIS was heavily damaged, and in the words of Helen "falling apart," when it finally met its end by crashlanding on Rykerzon. (AUDIO: World of Damnation, Sweet Salvation)