The first time it happens, Sherlock is just starting to drift off to sleep. His brain, though never truly quiet, has finally slowed as he allows himself to relax for the first time since he stepped off the ledge of St. Bart’s three years ago.
It's the slow, hesitant footsteps on the stairs to John's room that bring him back to full consciousness. It's when they falter in the kitchen with a controlled gasp (that Sherlock refuses to acknowledge might be a sob) that he understands. And it is when they, even more hesitantly make their way down the hall to Sherlock's room that he closes his eyes, steadies his breathing, and pretends to be asleep.
The door opens, but the sliver of light doesn't hit his closed eyelids. He cracks them open (because he has spent too long Not Safe to not check) and a bit of irrational relief floods him that it is John's silhouette in the barely open doorway.
The shadow stays there for several minutes, carefully steadying his breathing, before a relieved sigh fills the air and the door closes with a quiet click.
Neither mention it the next morning at breakfast.
The next time it happens, Sherlock hadn't slept in four days and is just starting to doze on the sofa. The closer proximity to John's room allows him to hear the startled gasp and heavy breathing that follow. Nightmare, his brain tells him. John had had them often enough before. Several minutes later, the hesitant footsteps are on the stairs again.
He hears the falter in John’s steps as he enters the main room. He wasn't expecting to find Sherlock asleep on the sofa, which is odd because before he... left... Sherlock slept on the sofa more than his bed.
This time, John does not stop at the doorway but enters the room, each step sounding like it takes momentous effort, to kneel beside his (apparently) sleeping friend. He just seems to breathe for several moments before the rustle of fabric warns Sherlock of the impending touch.
Sherlock restrains the instinct to grab the wrist attached to the hand slowly approaching his exposed neck. This is John he reminds his body and (of course) his transport listens because it knows just as well as he does that John would never hurt him.
He doesn't even flinch when he feels the two fingers press lightly against the pulse point in his neck but he does shuffle a bit in his "sleep" and allow his wrist to fall in such a way so it is exposed to John.
It's two more nights before John takes the sleepy invite to check the pulse in Sherlock's wrist (it isn’t coincidence that it’s the same wrist he used when Sherlock had been lying in a pool of blood on the pavement).
The breathy sob that the doctor makes when he finds a pulse there, too, makes Sherlock wonder whether he's helping or making it worse by playing along.
The final time it happens, Sherlock has already decided to let John know he knows what he's been doing. He has pointedly ignored his brother's advice to, for once in his life, show some tact.
John is John.
He does not need to be mollycoddled.
Later, Sherlock will wish he'd listened instead of replying with only harsh words and scouring the flat for all his brother’s hidden cameras.
This has been going on for long enough that Sherlock knows John's patterns. Knows where to hide so it will look like he's simply not in the flat.
He's dressed in his clothes and wearing his coat and scarf. His bed has not been slept in since John made it up two days ago. His dressing gown is hanging on the back of the closet door.
For all intents and purposes, it will look as though he has simply popped out for something. Conveniently returning just as John is leaving his room, easily leaving him the opportunity what John was doing there in the first place.
He briefly considers actually going outside (it is a cold night and there is always the slight possibility that John will notice his face will not be flushed from the cold) but John's visits do not occur at a set time and Sherlock has no way to predict when he will come so he regauls himself to waiting in the bathroom with the door open and the light off.
Besides that single detail, his plan is flawless. He wishes he could tell John. John would appreciate the elegance of it. The genius.
He ignores another warning text from his brother and, later, he will blame his annoyance at Mycroft for making him miss the one glaring flaw in his plan.
He is practically twitching with anticipation in his seat in the bathtub by the time he hears the tiny noises that hallmark John's imminent arrival.
There is a pained noise from the main room that Sherlock can't place, it sounds like it comes from where they keep the coats but Sherlock can't think of why the absence of his coat and scarf would upset John so he remains quite.
For the first time since Sherlock's return, there is a slight limp to John's gait as he walks down the hall. Sherlock puts the limp together with the pained sound from before and decides John must have stubbed his toe. Usually, if a stubbed toe is enough to cause a limp in John, it earns itself a few choice words from the ex-army doctor that would make a sailor blush, but Sherlock attributes the lack of curse words to the fact that John thinks Sherlock is asleep and doesn’t want to wake him.
John is courteous like that.
When John cracks the door to Sherlock’s bedroom, the tall man in the bathtub begins to rise to his feet but the strangled noise that escapes the doctor's throat freezes him in place with confusion. This, like the pained noise from the main room, Sherlock cannot place.
Emotions are... not his area.
John is usually the one that explains these things to him but John has disappeared through the doorway and (judging by the sound of the mattress) taken a seat on the bed. His brain is ordering his body to move. To go to John. To gather more data so he can know how proceed. But his transport is ignoring him and seems to be frozen in place.
It is the sound of the safety of a gun clicking off that finally spurs his body into action.
Sherlock, for once, foregoes his usual dramatics in favor of speed. Those few steps out of the bathroom and down the hall are the longest he's taken in his entire life (he includes the few steps back to the ledge after Moriarty had shot himself).
He finds John sitting on the bed with a gun to his temple. It's an odd feeling, this cold terror. The ice flooding his veins is certainly unpleasant.
"John," he gasps because for some reason his throat is tight and a gasp is all he can manage.
He wants to run to John. To pry the gun from his fingers. He wants the gun as far from John as he can get it. Hell, as often as they'd relied on it for protection in the past, Sherlock would happily throw it into the Thames if it got it away from his blogger.
He can get another gun but he can't get another John.
"John. John. John."
His transport is acting on its own again, muttering a litany of John's name over and over and over. But John doesn't seem to notice. In fact, John doesn't even seem to be paying attention.
His eyes are closed and his face is passive. John looks older and far more tired than Sherlock has ever seen him. Even more so than that case where John hadn't been able to get a proper night's sleep for just over a week and had survived on the few cat naps he’d been able to grab.
He doesn’t look upset, there are no tears on display or body wracking sobs. Instead, John just looks old, worn, and resigned.
The air of finality in the room scares Sherlock.
"Don't. Please, don't. John."
He's terrified as he finally forces his transport to inch forward. Never startle someone holding a gun. Keep them talking.
He's talked down people holding guns before.
He's talked people down from shooting John too.
He never thought he would be talking down John from shooting himself.
"Don't be so pedestrian, John.” It’s a weak attempt at normalcy and it falls completely flat. “Give the gun to me, please."
He's closer now. Halfway between the door and the bed. John's face still gives nothing away. Still does not tell him what triggered this.
"What's going on, John? Emotional motives have always been your area not mine."
He's almost in arm's reach, now.
"Explain it to me, John. You always love it when you know something I don't."
Relief so thick it nearly chokes him floods through Sherlock's chest when John lets off a quiet huff. Any reaction is better than nothing.
Almost... Almost... Almost...
"You're a figment in my head, you tell me," John finally answers.
Arm's reach. Sherlock starts to raise one hand. Slowly. Slowly. Don't startle.
"I'm here, John. I'm real. Let me have the gun?"
Sherlock's fingers brush the barrel. John flinches but his trigger finger remains steady.
"You got to take the easy way out," John answers. "Why can't I?"
"Death is boring, John. I've tried it." Sherlock's fingers slide around the barrel, grasping it. "You won't like it," he promises.
John's eyes finally open when Sherlock tries to tug the barrel up, to aim it at the ceiling instead of John's head. His blogger’s eyes are usually so bright, now they are dull and tired.
And he doesn't let Sherlock pull the gun away.
"If you're there, I'll like it."
"Don't be stupid, John," Sherlock scoffs, but there is still a tightness to his voice. The words bring a sad smile to John's lips though. "I’m not there because I'm here."
He reaches out with his free hand and brings John's up to his throat, fingers pressed to the pulse point once again. The pressure allows him to feel his own heart thrumming beneath John's fingertips. Faster than usual but it should be enough to reassure the doctor.
"I went out John," he tells him because he can't bring himself to tell John that he caused this. "I'm wearing my coat and scarf, see? They weren't figments or ghosts or whatever you've decided they were," he explains because Sherlock is a smart man (smarter than smart but that’s not the point) and even though he doesn't always understand emotional motivations or sentiment... given enough data he can usually put two and two together and draw the right conclusion.
John made a pained noise when he saw the coat and scarf were gone.
John aimed a gun at his own head when he found Sherlock's room empty and unused.
John made several comments alluding to Sherlock still being dead.
Conclusion: John believes Sherlock is still dead and that he imagined his return.
"You left," John states.
"Just for a moment, John. Just right outside. The gun, John. please."
Sherlock didn't realize he was still holding the doctor's hand to his throat until it twisted out of his grip and attached itself to his wrist instead.
Only when he finds the pulse in his neck duplicated in his wrist does John release the gun, leaving Sherlock holding it by the barrel. He flicks the switch that releases the clip and expertly disassembles it with one hand, not willing to withdraw the comfort of his pulse from John just yet.
He is surprised when he feels the side of John's head press up against his chest, but his transport acts on its own again and the hand that had been holding the disassembled parts of the gun comes up to hold him there.
They stay like that until John's steady breathing indicates sleep.
John does not cry nor does he sob. He does not whimper when Sherlock tries to move them into a more comfortable position on the bed.
Instead, the doctor just keeps an iron grip and utterly refuses to let him go.