"You have to be more careful. You can't- You are not allowed to die." Sherlock pulled John even closer, his face hidden in the crook of his neck.

John, who was underneath him, ran his hand through Sherlock's dark curls, and gave him a light kiss on the temple. "I'm fine. The doctors didn't even insist on keeping me overnight at the hospital, so there's nothing to worry about."

"You weren't breathing." Sherlock let out a shaky breath, pressing his lips to John's pulse point.

He dragged John's body out of the water, hearing the sound of sirens in the distance.

He immediately started heart compressions, his eyes glancing at the blow John had received to the head. He opened John's mouth, pressing their lips together, and breathed out.

Nothing.

He kept going, the sirens sounding closer now. He knew he was probably applying too much pressure; he was surprised he hadn't broken any ribs yet.

He pressed their lips together again and exhaled, bringing up a shaking hand to feel John's pulse. It was there, but slowing down, fast.

NonononoJohnyouhavetobreathyoucan't-

"You weren't breathing; your heart had stopped. You had a mild concussion, and it's a miracle I didn't broke any ribs. You are not fine."

"Sherlock, look at me." He pulled lightly at Sherlock's hair, seeking his eyes. "I know you were scared, but I am fine; I'm here." He frowned, concerned. "I've been in danger many times, we both have, and I've never seen you react like this. What is it?"

Sherlock closed his eyes and leaned forward to rest his forehead against John's. "Because... Because I finally tell you that I love you, and a week later you go and die on me. If you hadn't woken up-"

"Hey, all right, calm down," John whispered, pressing a kiss to his jaw and his lips. He grabbed Sherlock's hand, leading it to his neck, so he could press his fingertips against his pulse. "I'm right here, and I'm not going anywhere. I'm sorry if I worried you, but- Well, it's going to take a lot more than a swim on the Thames to keep me away from you."

"Promise me," Sherlock said, opening his eyes and staring intently at him, with such a raw anxiety that John could feel a lump forming in his throat.

"I'll never leave you," he breathed against his mouth, Sherlock's gaze piercing right through him. "I promise."