The Moment. It is was will be referred to in capital letters, like many other things on Gallifrey. The Moment. The one chance to end the war forever. To escape the infinity loop, always drawing closer but never touching, without end. Should he use it?
Will Not Do Not Did Not. It would condemn everyone except the one who used it. Last. He will be is was the Last of the Time Lords. Will Do Did. Tenses are unimportant now. This Moment contains all moments for Gallifrey—past present future.
Time Locked. Can he turn the key and walk away?