Originally Posted by Anno_Domini
"But if I did save you, I realize that you will see this as weakness on my behalf and come back from prison because I left you alive."
"That's why it's so important, it separates us from them."
I see the whole scenario as a kind of Saw like trap. Bruce is essence built a trap door and tied a noose around Ra's' neck, and Gordon was asked to pull a lever, and that is what makes him fall through and die.