Page "The Matrix Reloaded" Paragraph 5

Neo meets a program called the Architect, the Matrix's creator.

The Architect explains that Neo is part of the design of the Matrix, and unless Neo returns to the Source to reboot the Matrix and pick survivors to repopulate the soon-to-be-destroyed Zion, the Matrix will crash, killing everyone connected to it.

Combined with Zion's utter destruction, this would mean mankind's extinction, but the machines would survive on some lesser energy source.

Neo learns of Trinity's situation and chooses to save her instead.

As she falls off a building, he flies to her and catches her.

Then he removes a bullet from her body and restarts her heart.