John is sweating. The stress of being kidnapped and held by Moriarty and his goons had already peppered his hairline with beads of sweat, but it is nothing compared to the rivulets of perspiration down his back now that the horror and weight of the Semtex vest is added. When they manhandle him into the anorak, the heat is almost unbearable.

A voice cuts through the too-humid air. The unmistakable baritone echoes through the pool building, and John's hands, buried in the coat pockets, clench and unclench.

The locker room door opens to the pool, and he is hit by a blast of warm air and the smell of chlorine. He huffs out a steadying breath. John knows what is coming, knows what is expected of him in his role as the fifth pip. Knowing makes it worse. He dreads seeing Sherlock, and dreads Sherlock seeing him. He dreads hearing the madman's words, and dreads having to give voice to them.

He does what he is told, and turns to his right to face the man at the end of the pool. He sees the look of confusion on his friend's face. Worse, then. Worse than expected.

He hears the first of Moriarty's words coming through his earpiece.

Keep your voice steady. Neutral. Don't give Moriarty the satisfaction.

He repeats the single word, "Evening," his voice sounding foreign to his ears, as if his throat is held in a vice-like grip of Moriarty's hands. And then more words before...

"John? What the hell?"

Mercifully, John is told to open his anorak to reveal the explosive vest. At least Sherlock knows now that I didn't deceive him.

And so the dialogue continues. He tries not to watch the painful play of emotions on Sherlock's face as he plays puppet to Moriarty's ventriloquist. It is agonising, the voice in his ear perversely intimate. He delivers the wretched words in as much of a monotone as he can muster, despite his voice cracking.

"...the pool where little Carl died. I stopped him."

A tilt of the head as he listens to the threat spoken into his ear: "I can stop John Watson, too."

The hopes and regrets of a lifetime are encapsulated in one small gesture. It's not supposed to be this way.

His throat constricts even further. His voice drops almost to a whisper and he repeats the hateful words to Sherlock, knowing they might be his last.

oOo

"Sherlock, run!" John throws himself at the madman, restraining him.

Sherlock can't believe what he's witnessing. He's trying to save me. Why-?

He's trying desperately to concentrate. It's just another hostage, the voice in his head says, but now it's Mycroft's voice, not his own. Distance yourself, Sherlock. Distance yourself, or you're going to miss something. But he fails. This is different. This is John.

"Good, very good!" the maniac says.

"If your sniper pulls that trigger, Mr Moriarty, then we both go up." John's voice is steel; this is no idle threat.

Sherlock chances a furtive look around the room but his eyes come back to Moriarty as he continues to babble nonsense. It doesn't bother him, but it infuriates John.

"But oops!" Suddenly, Moriarty jerks his body to his left.

Sherlock doesn't understand why. His gaze doesn't falter from Moriarty's smug face.

"You've rather shown your hand there, Dr Watson."

He sees the doctor's grip on Moriarty loosen before John goes rock still, his eyes wide and unblinking as he stares at Sherlock's forehead. It doesn't take a Sherlock Holmes to deduce that he is looking at a laser's unforgiving red dot. Sherlock's eyes close involuntarily.

A tilt of the head down and to his right, a minute shaking of his head in disbelief. No!

The insecurities of a lifetime are encapsulated in one small gesture. Stupid! Stupid! The voices in his head are relentless. You underestimated Moriarty.

Mycroft's harsh voice echoes. You always miss something.

John's voice seals the verdict. It's how you get your kicks, isn't it? You risk your life to prove you're clever.

I've killed us, John. I'm sorry, Sherlock thinks, knowing that might be his last thought.