After the Reichenbach Fall episode first aired, the internet was abuzz with speculation about how Sherlock faked his death.  To me, this was a minor mystery compared to:

What the crap happened on the rooftop before he jumped?

The scene begins with Moriarty gloating because he had beaten Sherlock.  He seemingly convinced Sherlock that the only way to save his friends from snipers was to commit suicide.  Sherlock took a few moments alone and, after somehow deducing that Moriarty had a code to call off the snipers, convinced Moriarty that not only had he not beaten Sherlock but that the only way to have a chance was to shoot himself. 

Having finished series 3, there was as far as I can tell no further explanation of this scene.  Why did Moriarty kill himself?  The motive is clear in theory: Moriarty was convinced that the only way he could win was to shoot himself.  But the details are anything but clear.  What would Sherlock had done to snatch victory from Moriarty if he hadn't shot himself?  What did "victory" even mean, anyway?  What did Moriarty mean when he said "As long as I'm alive you can save your friends"?  Were any of these questions answered in series 3?