In the end, or the beginning, existence is motion.
At a scale too small for even Time Lords to perceive directly, superstrings vibrate in eleven compressed dimensions. The universe dances.
Except for Jack. Jack is still, even when he's running. Smiling, hugging, talking, flirting, Jack is dead to time.
Jack is/not. Jack is nonbeing. Worse than entropy: Jack is certainty, stability. And quantum stability means no big bang. No time, no space, no universe.
Jack is unmaking, and it's the Doctor's fault.
I am become death, the Doctor thinks.
He looks at Jack, his monster, his mirror, and he trembles.