Before I begin, i know very well, that this is most likely (in fact, almost definitely) not the right theory, but this idea just occurred to me the other day, and I don't think anyone else has commented on this (probably because this theory is pretty, to put it simply, rediculous), so may as well mention it. We all heard Moriaty say that he hired trained killers and told them to get the code from Sherlock (or something along the lines of that), and then as a result, they tried to save Sherlock's life, and then started killing each other so none of the other killers could get the code. Well, Moriaty told Sherlock that the code's a fake, but Moriaty might not have told the killers that. So, maybe one of them saw Sherlock falling, and, I don't know, somehow or rather, saved Sherlock's life? I can't really think of a way that he could save Sherlock's life, (eg. putting a mattress out probably wouldn't have helped, there is always a net but it would need more than one person to hold out). Yes, I know that this theory is most definitely not the right theory, but since when is it about being right anyway?