I wish I could say that I own Sherlock, but alas I do not. Characters belong to Moffat, Gatiss, and Conan Doyle.
I never thought I would write a Reichenbach piece, but I read a Martin Luther King, Jr. quotation while researching for a class project and this oneshot was born. I took some creative liberties here. I personally do not think Sherlock's plan was flawless; he probably had some misgivings while standing on the roof. I also think his tears and actions during the phone call were more genuine than faked, and that it killed him to do that to John. So, with that being said, enjoy!
Sherlock Holmes had always thought of himself as more machine than man. He could churn through the data provided by his senses and come up with several possible explanations for a murder, just by a preliminary assessment of the victim's body. He could judge a person's height from the imprint of his shoes, identify hundreds of different types of tobacco ash, crack codes and ciphers without breaking a sweat, and see through apparent suicides to the murder underneath. For so long he had separated himself from any emotion, closing himself off from the world around him. He had no use for sentiment; it would have just slowed him down.
Then a doctor invalided from Afghanistan had come into his life and slowly forced his way into Sherlock's heart, making Sherlock care not only for the medical man, but for the people in his world who he had never taken much notice of before. He had grown fond of Lestrade (though he would never admit it to the Detective Inspector) and more appreciative of Mrs. Hudson for her tolerance of his eccentricities (she had known what she was getting into, though). John had made Sherlock appreciate Mycroft (marginally) more. He had even begun to be aware of Molly's feelings and stopped (when John was around) using his charm on her, making it much harder for him to gain access to the morgue. Emotions were such an inconvenience, but Sherlock would not have wanted to go back to the time before John when drugs were the only things that aroused any feeling in his soul.
Ever since meeting Moriarty at the pool, Sherlock had frequently wondered if he would have ended up like the consulting criminal if he had been born with a predisposition for chaos rather than justice, destroying lives for his own amusement, to stave off the boredom of "staying alive." Despite John's misguided attempts to classify him as a hero, Sherlock had long thought the answer was yes. Now, as he looked down at Moriarty's still form, maniacal grin frozen on his face, Sherlock realized the answer had changed. Jim Moriarty lacked a heart, while Sherlock's was beating painfully fast in his chest. Before his demise, Moriarty had discovered that heart and set it on fire, just as he had promised.
He had not used matches. No, that would have been far too unoriginal. He and Jim did have one thing in common; they both liked high stakes, and what was higher than presenting Sherlock with a dire ultimatum on a rooftop above the streets of London: jump or the few people in the world he cared for would be gunned down. The old Sherlock might not have batted an eyelash at this (although new Sherlock was unsure if he had really ever been that heartless or if it had all been part of a facade). Now, Sherlock knew he could not let his friends die, even if it meant a self-imposed exile where his friends would presume him dead.
Sherlock watched as John pulled up in a taxi outside the hospital. He pictured the crosshairs of the sniper rifle centering on the doctor. Sherlock had seen plenty of horrific sights in his life, but he knew he would never be able to forget the image of John Watson taking a shot to the head and crashing to the pavement, never to get up again. No, that would be Sherlock's role to play.
Sherlock dialed John's number and began the hardest conversation of his life. Halfway through the call, Sherlock felt tears begin to drip down his face. For once in his life, they were genuine. He had a plan, but it was far from perfect. He hoped with all his being that he survived this fall, so he would have the chance to apologize to John for what he was about to put him through.
When John asserted that Sherlock could indeed be that clever, he almost broke. He couldn't do this to the doctor, his only friend. But then he pictured the bullets that would fly if he didn't, destroying three lives that could never be replaced, and Sherlock knew he would have to go through with his plan. He bid goodbye to John, tossed his phone onto the roof, and spread his arms wide.
Strangely enough, certainty had forced down the fear that had been threatening to paralyze him. After all, as Moriarty had said, falling was just like flying, but with a more permanent destination. If all went as planned, his final destination would be 221 B Baker Street, but he knew not whether that would be months or years from now.
As the wind whistled through his hair, something he had once read sprang to his mind; "No one really knows why they are alive until they know what they'd die for." Sherlock existed to solve crimes and bring killers to justice, but now he had something else he wanted to live for: friendship. He could die for that. In the end, this was what separated him from Moriarty and made him more than a mechanical crime-solving contraption.
I'm so sorry, John, Sherlock thought to himself as he took a deep breath. The consulting detective stepped off the roof of St. Bart's…
And he fell.