John really can't believe what he's seeing. The way Sherlock's eyes dart all over the room as if he is expecting something to jump out, the way he nibbles at his lips and the way his hands are trembling, but it's not cold in there. He's muttering, then silent, then shouting, and John is scared, too. John is scared about what Sherlock might do. What Sherlock might say.
And as he starts spouting out deductions, John can't take it. He just can't see Sherlock like this.
Arms wrap around the consulting detective. They hold him for a moment; not too tight, but just enough that Sherlock stops talking. He is frozen, his breath puffing out so gently against John's exposed neck, as if Sherlock is afraid to even breathe lest John were to do anything more than hug him.
"Why won't you listen to me? I'm just your friend."
Somewhere in his eyes, Sherlock is a scared child. He looks like a little kid on the brink of tears, like little Kirsty probably looked upon discovering Bluebell's disappearance, like how Henry Knight must have looked as he watched his father being ripped to shreds. But he also looks angry; angry and disturbed and furious at his emotions. John doesn't like this side of Sherlock. He could burst at any minute. He had the power to hurt with his hands, and even though John was a soldier, the unpredictability of Sherlock in this mental state was more frightening than any man with a gun.
Yet, Sherlock doesn't fight John back. From his mouth escape four words that hurt John more than any punch, any scratch, any bullet could ever have.
"I don't have friends."