Disclaimer: No, I don't own BBC
Sherlock knew what was going to happen as soon as Moriarty reached for the gun. For one of the few moment in his life, he panicked. Then Moriarty pulled the trigger.
The bang was short, and it was muffled, ironically, by Moriarty's skull.
Time seemed to freeze as Sherlock's mind raced for solutions. The assassins were waiting. Waiting for the signal that was now readily unavailable, or for Sherlock Holmes to fall off the building.
There was no way Sherlock was going to let anyone die for his miscalculations. He was angry at himself for letting things go this far. As he walked to the ledge, and stepped onto it, he couldn't believe the how blind he'd let himself become. He had enjoyed "playing" with Moriarty. He led Moriarty on and Moriarty had followed quite willingly. And now, because of it, he was going to have to let go of the only people who had ever really made him feel human.
He deserved it, he supposed.
The cab, which was undoubtedly carrying John, pulled up to the curb on the other side of the road.
And so it begins.
He pulled out his phone and texted his brother: I'm going to fall. Make sure it's your medics that get to me.
There's a beep and he gets a text back: Are you sure you want to do this?
Sherlock grimaces. He doesn't bother texting back. He knows that below him, his brother has made a top priority call and specific government nurses and doctors are being readied to race out at the first cry of horror.
It's a good thing the street is getting more crowded.
John has stepped out of the car. Sherlock braces himself and presses the name on his speed-dial. John picks up the phone.
The first thing John does is race towards the building. Sherlock feels his heart breaking as he tells his friend to remain on the opposite side of the road. John can't be close to the scene. It would ruin everything, no matter how much better it would make Sherlock feel.
That's when he realized with dull amusement that he had a heart. And it was being ripped out. And he was the one doing it. How people could say that they ripped out their own hearts?
Sherlock heard his voice crack as he told John to stay away. That wouldn't do. He closed his eye and calmed himself. When he opened his eyes, he found he could talk normally.
Good. Now for the apology. The apology to a best friend for being the biggest, most conceited idiot in the world.
"I'm a fake," Sherlock heard himself say, and he meant it. Oh no, the emotion was back. This time however, he didn't try to push it down. He needed John to hear this – at least once. He created Moriarty. He had practically created him.
Then he lied about looking up John's sister. Of course he hadn't looked up John Watson's past. But he didn't deserve his intelligence, so he might as well have.
To his surprise, he felt a tear run down his face.
It was time to give the biggest lie of all. Oh, how he hated the sound of anguish in John's voice. But he would get over it. John had a big enough heart. It would heal quickly enough.
Sherlock pursed his lips, and he said good-bye. He wasn't going to be able to see any of his friends for a very long time. But he deserved it.
Now for the moment.
Silly people. For once, he was glad that his outfit had become such an icon. People probably wouldn't recognize him without it.
Which is why no one, except a few government doctors sworn to secrecy – and Mycroft (he owed Sherlock after all)– realized he had pushed Jim Moriarty off the building. It had been Jim Moriarty that gave him the idea after all.
"You are me," he'd breathed. So it served to reason that Jim Moriarty could be Sherlock Holmes for a while.
Then there was the reason he'd kept John on the other side of the road. It wouldn't do to have him run up and identify the body. To Sherlock's satisfaction, the paramedics his brother had sent out did a good job of keeping him away. If he'd seen the face at all it was bound to be a bloody mess.
He had shot himself in the face after all.
Sherlock counted on the shock to keep John from recognizing that all the blood was in the wrong place. And he was right.
He stayed on the roof until sundown.
No one had come up.
Who would think to check? In their eyes it was a suicide. No need to find evidence. Good thing they hadn't, it would be a bit difficult explaining the blood.
Hm. Better have his brother send someone to clean that up.
Now that it was over, Sherlock felt a weight lift from his shoulders.
He had a job to do.
Author's Note: I know this doesn't explain everything. But I realized someone had to fall off the building and unless Sherlock had super powers or did something exceedingly brilliant, I doubt it was him that fell off the building. (Unless he gave in to his melancholy and did idiotically throw himself off the building and accidentally survived). Or... it could be something one my readers mentioned to me. That was good. In fact they're probably right.