So. Here we are with the final establishment – for now. This is set during the timeline of chapter 2. It is a in depth account of Sherlock's breakdown, and I'm not sure if any of my readers have ever had a nervous and/or psychotic breakdown (if so, I send hugs) but if you have you know the nastiness that it entails.
That said, you may have an idea of what you're about to get into. If not, this is insanity, pure and simple. There is a lot of self harm in this chapter, and references to depression and suicide. Sherlock may seem OOC, but keep in mind that I know this and that I've tried my best to accurately describe a state in which you completely lose your head and all but become someone else for a time. If any of these above things are going to bother you in the slightest, please DO NOT read this chapter.
And now I've kind of spoiled the chapter for all of you :D Ah well.

It had been stupid, stupid. A stupid idea. Sherlock was astounded at his own stupidity. If it had been John's suggestion, John's idea, well, that would have been one thing. John, although intelligent and tolerable and far from mundane, did have a tendency to say the most idiotic things at times. But this was himself, Sherlock Holmes. He was clever, always clever, all he ever had was his intelligence, and he should not give into fits of sentiment like that. Ever. He was a machine, always working, stripped of his humanity – but that wasn't quite true, now, was it.

John had brought back some of that humanity when he limped into Sherlock's life. Sherlock hadn't realized what had been missing until he was running across rooftops with John, eating in cafes with John, laughing and talking with John. When he was with John he could feel everything. He had been numb and cold and he'd thought he liked it but John had taken the machine in his hands and stroked it, rubbed some warmth back into the cold metal workings.

It didn't really matter that he could feel. He'd discovered that there wasn't anything wrong, per se, with feeling. It did not have the ability to affect his logic and deductions because feelings were associated with John – what he felt about John, how John felt about things. They did not enter into cases. But Sherlock was not allowed sentiment. Not ever. Not with John, not with work, not with anything, because sentiment was crippling and useless. It was what destroyed humanity. Feelings could, in the right hands, become weapons. (After all, an angry, grief-stricken man is a thousand times more dangerous than an indifferent one.) But sentiment could never be a weapon. Sentiment just ruined its owner. It was purposeless, useless. He was not allowed sentiment. Ever.

Sherlock had felt better that morning. He wasn't sure why. He thought that maybe his shagging John had helped channel out some of those feelings cluttering up his head, or maybe it was just a lovely day outside, but either way he felt lighter that morning. He wasn't happy, and he wasn't okay, but he was good enough to cook toast (if that was really considered cooking) and good enough to tease John, good enough to chase him around the house and catch him with a kiss. When he was sufficiently late to work, John ran down the stairs yelling "I'm stopping at Tesco's after work so I might be a bit late…don't break anything, I love you," over his shoulder, and Sherlock was left standing in the middle of the room in his dressing gown, grinning like he was completely deranged (which was possible) and feeling like he would burst from love and a brief fleeting feeling of happiness (which wasn't).

Things had proceeded somewhat normally from then on. He'd taken a shower and eaten his now-cold toast and begun work on his latest experiment, which involved a human brain (not fresh, sadly) and its response to different types of stimuli – something that had already been done, for sure, but he was sure he could find something that those ordinary people hadn't. Inside, he had felt almost balanced. For months he had felt empty, void of everything, feelings, ideas, everything; or full of anger and passion and darkness that couldn't escape, always crushing him, surrounding him, drowning him; and now he was halfway to stable. What a blissful feeling it is, after months of up and down and tumultuous noise and living a nightmare to finally balance out! After all that agony, the eye of the storm surrounds you with calm and everything stacks itself precariously on the scale of dark versus light. (Sherlock's scale had a little more black than white, but that was to be expected as he was clinically depressed, after all.)

He was concentrating so hard on those goddamn feelings that he wasn't thinking rationally. We said before that feelings didn't impede his deductions, and that was true. But he couldn't have both systems working at once. His feelings, his emotions, were soaring higher than the sky and crushing all rationality into the dirt. He was thinking at his normal pace, but he wasn't analyzing and processing properly.

He didn't even notice what he was doing, not after he picked it up, not after scales and arpeggios. It was his body's fault. It was acting on what had been pure habit, because Sherlock expressed happiness through his violin and now he was through the etude and onto Shostakovich.

It was a good choice. The third movement was safe. Nothing hurt because although it was technically difficult, it wasn't that strenuous. And Sherlock was enjoying himself, just letting everything go away, all his walls breaking down and he felt so relaxed and happy and he honestly couldn't remember the last time he had been okay like this. Had he ever been okay, really, properly, okay? It was impossible to tell. But he didn't care, because he was okay NOW and that was all that mattered.

The octaves just fluttered by. His hand didn't even twitch. Muscle memory was such a remarkable thing, really. Even after all those trials and all this time, his fingers remembered the exact amount of space between the As and the F-sharps and everything else in between. He was a little worried about the cadenza, but that went by easily as well. He was fine, now, it had just been his transport acting up, and it was healed now. He hadn't even needed surgeries. How silly, to get so worked up about something so trivial.

It was halfway through the burlesque that everything fell to hell.

He was climbing up and up and reaching higher and higher for the harmonics and then he went back down for the G string and that was when everything exploded. Inside his wrist, that is. Something inside ruptured (or at least it felt like it) and he snatched his hand away, completely forgetting the laws of gravity and the violin slipped out from under his chin and fell just like that.

That wasn't what ruined Sherlock, though. Don't think for one second that the fall of the violin, or even the failure to play, was what caused him to really, properly lose it. He was past the failure to play, actually. The violin had gone. He had taught himself to cope, albeit not well. The violin had come back. Not really. Sherlock deleted things and already he had begun the process of deleting emotions and events that were closely connected with his music. It was okay that he couldn't play, really. It didn't seem like it at the time, but that wasn't the biggest issue.

He was furious that his body had dared to defy his mind, to directly disobey him. It had wanted to play, after all, and when he had properly realized that he was playing, he had decided that he would continue. And now his transport was rebelling, acting against him.

Then this wave of realization slammed into him and his mouth dropped open and his other hand dropped the bow that Mycroft had thoughtfully had repaired.

He had been wrong.

It hadn't been his transport's fault.

His brain had been wrong.

Sherlock was never wrong, ever, about anything. He just wasn't. He was the one people feared and hated and shunned because he was always, always right. He wasn't wrong. That could not be, it could not even exist as a possibility, because the word "wrong" could not apply to Sherlock.

But it could.

He had kept going because he had thought he could do it. All the while his body had protested and he had ignored it, dismissed those little twinges during the augmented arpeggio and the sixteenth notes in the beginning of the burlesque. It wasn't that he hadn't been able to so much as he had been wrong, not about some mundane ordinary person, but about himself. His own hard drive had been wrong about his own transport.

That was not acceptable.

If you have ever felt like Sherlock, if you have ever snapped like he did then, you might remember the one action or word that triggered the disaster that came next. Once that thing was out there, you were raw. You were primal. Reason wasn't there, judgment flew out the window. And you did something horrible, something twisted and sick, something so stupid to try and punish yourself, to make yourself pay for your mistakes.

Sherlock couldn't help that he had been wrong. He couldn't reverse it. So he pushed that incorrect deduction back to the bonfire of rage and action and energy burning in his mind and used it as fuel to help him act on what he could control – his disobedient transport. Not his mind. His transport. His focus, his plan, was to punish his transport for not working properly. It was transport. It had to do what he said, and when it didn't, he had to make it.

He got so worked up and angry; he was pacing back and forth for an entire hour literally tearing out his hair trying to decide how he could handle his transport and then a nasty little idea popped into his head. There were all sorts of transplants nowadays, and Sherlock knew how to perform most of them, and he got it into his head that he could easily remove the nerves, the tendons, the bones, everything inside his left wrist that was causing the problem.

So he tried to.

But it was so awkward, and so hard, and he couldn't cut the vein vertically because then he would bleed out in approximately 15 seconds, which would make it very difficult to perform a successful transplant. So he tried horizontally, which REALLY didn't work, and then there was blood everywhere and he then realized that he didn't have any nerves or tendons or bones to replace his faulty ones unless he used the ones in his right hand, and he tried to get at those but that didn't work either – and then he realized, after he had really and truly failed and acknowledged that he could not perform a transplant, the most important thing of all.

Now that he had failed, John couldn't find him alive.

There was blood everywhere and Sherlock had broken several things downstairs and a few more upstairs here in the bedroom and he had used JOHN'S razor, not his own, and oh, God, how could he have been so stupid? He had failed his last desperate attempt to fix himself and now he had to die, to leave, so that after John sent the violin into the repair shop and threw out the sheets and bought a new razor, he wasn't left with a Sherlock who needed fixing, too.

Sherlock didn't care about the dying lark so much as how badly he had failed at this suicide thing. If he had really wanted to slit his wrists, he could have done it so much more efficiently. It would all have been over in fifteen seconds or less and now the bedroom was a disaster and he was a disaster and God, what a sick fuck he was not to kill himself properly earlier in the day when he first picked up the razor. Preferably with much less of a mess.

But now he was stuck in this, and he realized that he had pretty much wrecked John's facial razor, so Sherlock went downstairs and dug the X-Acto knife out of a kitchen drawer that normally held the cheese grater. John had attempted to hide it again, but Sherlock always found things that John hid. He examined the blade, making sure he hadn't damaged it on those kidney stones a few weeks ago, and then went back upstairs, taking care to wipe the blood off the counter before he left.

He calculated he had about two hours left before he bled out through his wrists, and he wondered what he was going to do with all that time. And that was when another nasty little idea popped into his head, because after all, you never, ever got to experiment on a living human nowadays. It was unethical. Unless that living human was doomed, and that living human was yourself, and that living human had already died inside anyway…

It was remarkable, the results of the experiments. It was so different working with an actual body that still had life left in it. He examined the layers of the fingertip first, but he hadn't thought that it would bleed quite that much, so he found a lighter in the nightstand and used it to cauterize the wound. And then he looked at the structure of the ankle, which was absolutely fascinating, and something he would rather have liked to approach further if he hadn't only an hour and a half left to live.

Well, he had only an hour before John came home now. He would have to hurry this up.

Then he realized something that made him cry for the first time that afternoon. He had not cried when he couldn't play, and he hadn't cried when he had started cutting, and he hadn't cried when he switched to the X-Acto. No, only now was he crying.

John had dashed out the door that morning and yelled that he loved Sherlock and Sherlock had not told him that he loved him back.

Now he couldn't.

Sherlock knew just how mad this was. He was killing himself, had sliced himself open in several places all over a violin, for Christ's sake, and now he was crying because he hadn't told his husband he loved him. It was absolutely ridiculous. Sherlock was ridiculous. Another reason to just get rid of himself.

Sherlock wasn't going to carve something like that into his body. That was going too far. And he wasn't about to write it down, because he was starting to feel a bit dizzy and he didn't think he would be able to get up and find a pen and paper.

Then the nastiest idea of the lot popped into his head. It was really quite twisted and horrible. But he was dying. When you are dying, anything goes.

John loved paintings by Renaissance people, mostly. Vermeer and things like that. But Sherlock remembered that he had really, truly loved Van Gogh. They had been at a museum for a case and they had gone into a gallery full of Van Gogh and John had looked so excited and happy that Sherlock had immediately saved it to his hard drive in the folder labeled Things that will never, under any circumstances, be deleted. John would understand the reference, in any case.

And before Sherlock had time to change his mind, before what tiny bit of reasoning was left had the chance to persuade him to stop, he had grabbed the X-Acto knife and sliced off a good portion of his left ear.

It was only an ear, Sherlock reflected. But he felt ridiculously lighter now that it was gone. Something told him as he held that bit of ear in his hand that he was sadistic, insane, that his hard drive had been corrupted with a virus, and then a revelation hit him and he threw back his head and laughed.

He knew the virus well.

Emotion. Sentiment.

It was what had led him to pick up the violin. It was what had led him to slash his wrists and attempt an impossible transplant when he couldn't play. And it was what had led him to just cut off his ear, which had been one of the dullest and most clichéd things he had ever done, now that he thought of it. He should have carved his love for John into his chest, his stomach, his legs. He obviously hadn't loved him enough.

Hadn't loved him enough.

What a paltry emotion, love. So insignificant against something this powerful. To think that he could have fought depression, anger, all of that, with something as weak as love. How silly of him.

Some people would ask how this could be. How a man, who had loved another man so much, with all the heart he had left, could lose all that in a matter of minutes, one slip of a razor blade, and errant thought processes. How he could revert back to the machine in under ten seconds, with no regrets whatsoever.

Sherlock Holmes was dying. He had gone insane. He couldn't think because he had lost too much blood. To him, that stupid mistake had signified the dangers, the idiocies of passion and romantic attachments. By cutting off his ear, he had finally discovered how to keep his feelings from dominating over his reasoning. And his newly restored reason, properly active again for the first time in months, told him that love wasn't worth it.

He had removed it. All of it. Human shortcomings and feelings, love and anger, everything was gone and look at him now, he was triumphant and if he could do this to everyone he would become God.

It was to be his last discovery, and what a fitting one, too. He felt a bit dreamy. It was getting difficult to concentrate, to think properly. The sheets were very shiny. He hadn't thought they shone so brightly when he bought them, but now they were positively glistening. How posh. Perhaps 300-thread count was good for something after all. He'd have to pass it onto John.

John! The experiment!

John would so love to know the results of Sherlock's experiment. Perhaps then Sherlock would be remembered as a revolutionary instead of a failure. Reason told him this wasn't likely. Still, even though he had been wrong to love John, to let anyone get that close, he concluded that John was just as clever as he had been at the beginning of the day and that John would be interested in something so avant-garde. With the last bit of strength he had, he wrote down the result in the only place he knew John would find it (in as precise a manner as possible, so as to leave no room for misinterpretation).

Then he saw the time out of the corner of his eye and without having any time to reflect on anything, to change his mind, he tightened his grip on the X-Acto knife and made the final cut.

One hundred and twenty long seconds passed. What came after twenty? Was it twenty three? Sherlock was missing something in between, he knew it. But he was just so dizzy now. And his chest hurt a little bit. It was hard to keep his arm from slipping off the edge of the bed. Or keep his eyes open.

The razor clattered down onto the floor as the hand's grip slackened and the arm fell off the bed.

And then the only sound in the room for the next eight minutes was the steady drip, drip, drip of red liquid pearls rolling off the pale index finger onto the floor.

In case you are wondering - the pieces Sherlock was playing were the third and fourth movements of the Shostakovich Violin Concerto No. 1 in A minor, the Passacaglia and the Burlesque, respectively. They're pretty cool pieces and extremely difficult technically.