Ultimate Sanction

A rhythm of four... the heartbeat of a Time Lord!Rassilon

Proposed by Rassilon as the last resort to winning the Last Great Time War, this plan involved the creation of a paradox so severe that the resulting spatial-temporal rupture would rip the Time Vortex apart.

An otherwise suicidal measure, Rassilon then devised a way of allowing the Time Lords to escape the disintegration of Creation by having the whole race shed their corporeal bodies and become creatures of consciousness alone, ones that would escape the effects of time and of cause and effect. (DW: The End of Time)

This plan was foiled when the Doctor came into possession of the Moment and used it to not only destroy every last participant of the Last Great Time War (DW: The End of Time), but also to place a time lock on the Last Great Time War itself. (DW: The Stolen Earth)

Nevertheless, Rassilon nearly succeeded in this mad plan when his sleeper agent, the Master, used the Whitepoint Star diamond, that he had sent to Earth, in a nuclear bolt as a way to send a physical rhythmic signal of four beats, the heartbeat of a Time Lord, into time and space. Rassilon then locked onto that signal to use as a homing beacon through which he could use in order to break himself, and Gallifrey (in addition to every other participant of the Last Great Time War), out of the time lock and begin the End of Time.

However, Rassilon was once again foiled when the Doctor used Wilfred Mott's old service revolver to destroy the White-Point Star, the key component of the signal being generated by the nuclear bolt that allowed the escape from the time lock, and Gallifrey was plunged back into its last day; the day when it burned. (DW: The End of Time)

This event was forseen by the Ood (Planet of the Ood), Carmen (Planet of the Dead) and the Trickster (The Wedding of Sarah Jane Smith). They all tried to warn the Doctor through riddles, which also informed him of his upcoming regeneration.