Sherlock takes a step back from the rapidly spreading pool of blood and allows himself a small smile. There's the tiniest niggling doubt at the back of his mind that this is too easy, all of it too easy to be true, but he is so achingly relieved that the mad man in front of him is finally dead, that he pushes it aside. Dead, dead and gone far beyond the possibilities of hurting John again.
He shuts his eyes, staggers slightly as the relief finally begins to sink into his bones. He can taste the crisp freedom of a world without Moriarty on the tip of his tongue and it makes him want to laugh.

No – time for that and plenty more later. Now he has to go, get back to Baker Street, back to John, apologise for those things he said, those things he made John believe to keep him safe. To laugh and push him upstairs into the flat and revel in the warmth and safety and familiarity of home. Of the kettle flicked on to boil, the slow tap of John detailing their latest grand adventures and escape, the steady drip of the kitchen tap that neither of them are inclined to fix, the rush and noise of traffic beyond the windows and the slow comforting brush of John breathing quietly into the stillness settling between them.

Sherlock almost falls down the stairs, tripping over his own feet in a mad dash down the spiralling depths until he emerges, blinking, out into the sunlight again. He needs to call Lestrad, tell him about the body on the roof, the blood congealing around slick backed hair, the smile tinged with desperate madness that belies the mess of flesh and matter gouged out behind.
Later, later, time for that later. Time for everything later.

He hails a cab, fidgeting, with his gloves, the line of his trousers, the edge of his coat, everything and nothing as he ponders what to say to John to provoke his forgiveness. He cannot help but go over and over John's words 'you machine'.
Yes, yes, I'm sorry, I had to get you out, had to keep you safe.
The twist of anger, of disappointment over Sherlock and his lack of quantifiable emotion. The hurt that pooled in his eyes, darkening them even as his lips quirked into a sneer.
Sherlock wants to smooth away the anger, whisper words of apology that drop like stones into the depths of John's mind. Ideas and soothing pleas to slide into the creases in John's thoughts and persuade him to forgive, to forget, to let Sherlock back in again. Open up with that soft, brilliant smile that John saves just for Sherlock and the swift swipe of a finger across the inside of Sherlock's wrist that tells him all is forgiven.

Baker Street, and Sherlock is already fumbling with the notes for the driver, sliding from his seat and from the cab before it's even fully stopped. Three quick strides across the pavement before he is brought up short by the sight of the door not quite caught. A tiny detail, innocent and glaring, that sends a shard of ice straight to the pit of Sherlock's stomach.

He pushes the door open slowly, senses alert for anything wrong – the odd discords of someone out of place, that push the familiar notes of home into a pattern of alarm.
The house is silent, the door clicking shut behind him and blocking out the sounds of city life behind him. A toolbox, various pieces strewn across the floor haphazardly. Stepladder, knocked at a forty three degree angle by someone pushing up the stairs in a hurry. Running? Desperate?
Scuff marks on the stairs, slight darkenings where a shoe has been scraped along – walking up the stairs backwards? Protecting from an oncoming threat?

Sherlock steps up – one, two, three steps. Wallpaper broken, plaster dust caking the wood below from cracks that radiate out across the wall. A body (head?) slammed into the wall at force.
Another step. Spots of blood on the bannister. A slight crack in the wood where it was wrenched abruptly to stop a fall.
Three more steps, the half way landing and the traces of blood are more obvious here, a fist fight of sorts. The carpet pulled up in creases to show the map of footprints and placements throughout the fight. Here, scratches in the wallpaper that show a smaller man pinned against the wall, zips and buttons catching and ripping at the paper. Then a punch that must have felled the captor – a more distinctive mouthful of blood spat out to catch at the windowpane and ledge.

Sherlock's eyes turn unwillingly to look at the half closed door to the flat. Silence. No quiet breathing, murmurs of encouragement or soothed reassurances. The ice has spread, he can barely persuade his limbs to move – awkward and disjointed as they felt when he was fourteen and nothing but sharp angles and protruding bones that constantly knocked into things.

He wants to run up those last few steps and shove the door open and reassure himself that everything is fine.
He wants to run out of the flat and pretend that this is not happening.
He wants to stand here in this limbo of not knowing because not knowing is better than the terrible dread that is coiling inside and threatening to choke him, to pull apart his reasoning and leave him hollow and empty.

He takes the last steps slowly, carefully. Noting the splinters of wood where a head made brief contact, the blood that flecks the wood and wall, the angry slashes to the wallpaper just by the door as someone tried to force it open.

Sherlock shuts his eyes, swallows, and pushes open the door.

For a moment there is nothing but silence and the harsh ragged edges of his breathing, frantic, spiralling out of control until he thinks he might faint.

Sprawled across the floor in front of him is John.

For a moment he stares and then his knees buckle, finally giving out beneath him. He crawls, sharp, desperate motions, trying to ignore the dampness of the rug beneath his hands and knees, the sharp metallic scent of blood as it coats his palms, engraining into the lines of his hands as though it's trying to fuse with his body. It's cool to the touch, and Sherlock tries to push out the knowledge of what this means, this quantity of blood, spread this distance across the floor, cold and tacky on his skin. He refuses to acknowledge what his brain is logically pointing out must be the truth, because he cannot bear to accept this truth.

This truth where John's skin is cool beneath his fingers. Where he cannot find a pulse, not in his wrist nor thrumming at his neck. Where John does not respond as he shakes and pleads and begs him to come back. Where his eyes continue to stare sightlessly at the ceiling above, blind to the desperate edge that's coating every word that Sherlock pushes out past numb lips.

Sherlock looks around the flat, frantically trying to find something to cling onto that proves that this is all a terrible nightmare, some anomaly that shows that he just has to push hard enough in the right direction and he will wake up. Wake up in his bed and John will be whistling in the shower as another day unfurls between them in the heavy sleep soaked confines of the flat.

Desperate to find something – not the body of Mrs Hudson sprawled inelegantly across the sofa, clean head shot showing the mess of flesh and bone shattered from the bullet. Not the position of the bodies that show that John was trying to protect her, a failed and stupid attempt to keep her safe.

Sherlock's eyes come back to John, they can't seem to stay away. Fingers plucking uselessly at his sleeve, his shirt, his collar, smoothing the hair back from his forehead and rearing back as he leaves ugly red streaks across John's face.
His hands flutter fitfully over the bullet hole, clothes ripped in its violent passage through to John's heart. A little lower than the original scar from Afghanistan – Sherlock can hear a keening sound of grief but can't correlate the noise ripping free of his throat as belonging to him.

This wasn't supposed to happen. The villain was gone, the evil defeated. They were supposed to laugh and drink tea and John would blog about it and tell Sherlock off for sending him away in the first place, and god, Sherlock should never have let him out of his sight. Not for a second. Not for anything.
Sherlock curls over him, strings cut as he folds his length against the hard compactness of John. But it isn't John, not anymore. This cold body underneath him has none of John's warmth or humour, or that sly smile just before he was about to go along with something ridiculously stupid that Sherlock had suggested. It smells of blood and death and destruction and the saltiness of tears Sherlock hadn't even realised he'd been crying, not tea and toothpaste and cheap shampoo and the dark comforting smell that was so fundamentally John. That had crept into the flat and Sherlock's mind and made him think of chases through rain slicked streets and a warm hand on his shoulder pulling him back and the steady hand on the gun, and that brief moment in the darkness at the end of a chase where something would tighten between them and anything seemed possible.

Gone. All gone.

Sherlock doesn't know how long he lies there, as the shadows lengthen across the room and the blood congeals beneath his fingers and he clutches desperately at the thing that once was John. He shuts his eyes and pushes himself away from it all, back to a point in his mind where he asked Mike Stamford for his phone and found himself caught in the steady gaze of John Watson.