Then you understand what would happen if both universes were to merge and try to occupy the same space.

[He finishes one string and moves to another, jumping from place to place seemingly without any sense of logic until Spock asks that question. His pen freezes mid-number.]

...My son. My only son.

As if God himself were punishing me for what I did over twenty years ago. He asks for my son as the key to stopping the destruction of our universes.