Jeremiah corners Lelouch, but he has a device that will disrupt Jeremiah's cybernetics.
Jeremiah asks why Lelouch became Zero. It turns out that Jeremiah was in Lady Marianne (Lelouch's mother)'s honor guard. His first loyalty is to her, not V.V.
He joins Lelouch's side.
Shirley runs in to help, and meets Rolo doing the same.
After a tense check that they are really on the same side, she tells Rolo that she wants to help make Lelouch happy. To help him reunite with Nunnaly.
That's why he finds her lying in a pool of blood. She dies in his arms.