Sherlock shoots straight up in bed, John's name on his lips, his quaking voice broadcasting his inner agony. John is there, almost immediately. He sinks down on the bed beside Sherlock, wrapping gentle arms around thin, trembling shoulders. He strokes Sherlock's hair, rubs his back. Even his very presence is calming. Sherlock can feel the tension in his neck and back melt away. He holds him in his arms, comforting him. With John right next to him, Sherlock can forget the flames, forget the water rushing, rushing everywhere, stealing the air from around him, stealing John's hand from his grasp. He can forget the pain, when he first came out of the water and John was still under it. He can forget that Moriarty is still alive, that John still isn't safe. John reminds Sherlock to breathe, in and out, in and out, slowly, that's right, I'm here, I'm safe, it's just you and me. John's touch is comforting and warm. It doesn't steal the heat from his body like the cold pool did. His voice is soft and deep. It doesn't remind him at all of the shrill lilt of Moriarty's taunts. With John holding him, rocking him to sleep, humming some soft lullaby, Sherlock isn't afraid anymore. His friend is right here, and there's no need to be afraid because he hasn't lost him at all, it's just a nightmare. John's fingers interlace with his own, and they sit there for a while, John rocking them both back and forth, Sherlock relaxing into his embrace. John starts to tell him something; says his name. But now Sherlock can't hear John very well, can't understand the words he's speaking, and the room is growing cold and it is getting hard to breathe and suddenly Sherlock is awake and he blinks back the tears, even though there's no one to see, because as wonderful as his dream was, as much as he loves being able to pretend he isn't gone, it makes waking up to an empty flat that much harder. When he cries this time, there is no one to hear, and when he sobs John's name, no one comes.