So this chapter is going to be sad. Also, I've kinda switched Sherlock's POV to 3rd person without realizing it so I'm gunna just keep it that way unless it serves my purposes to have in be 1st person again, in which case I will tell you in advance that that is what I'm doing. I hope people are actually reading theses things, otherwise this might get confusing. ;)
Sherlock stretched, then groaned. He had a headache and his throat was sore. His face was buried against something warm and solid. When he remembered what'd happened he wrapped his hand around the fabric by his head and squeezed his eyes shut. John was leaving. John was leaving to go get shot at. But he hadn't left yet. Maybe Sherlock could convince him to stay. Or he could just refuse to move. But no, John was shifting slightly.
A warm hand ran gently through his curls and he purred inspire of himself. John chuckled. The vibrations helping to soothe his headache. The hand stopped petting him for a moment but Sherlock nudged his head against John's hand. John huffed and said teasingly, "Are you a cat?"
Sherlock grunted.
A moment of silence and then John said, "I should be going."
Sherlock ignored him and moved so that he was more fully laying across John's lap. John wasn't going anywhere even if it meant Sherlock had to attach himself to John's leg like a 3 year old. He. Wasn't. Going.
...
John tried prying Sherlock's fingers off his shirt but Sherlock just ignored him and grabbed a fistful of his shirt with his other hand. John tried moving to stand up and Sherlock wrapped his arms around John's neck. John tried making as if he were falling over but Sherlock just balanced them. John tried standing and moving and Sherlock wrapped his legs around John's waist.
"Sherlock, I have to go." Sherlock buried his face in John's neck and said like a petulant two year old, "No."
John kissed Sherlock's forehead, sat down and rearranged Sherlock so that he was sitting sideways on John's lap, and tried to give him the glass of water. Sherlock refused to loosen his hold on John's neck so John held the glass to his lips and helped him drink.
"Stay."
"I can't."
"Please, you're my only friend."
John felt as though his heart was wrenching out of his chest. "Your brother has given me an ultimatum. Either I stay here with you and spy on you, or I leave and never talk to you again."
"Stay."
"I won't spy on you."
"You don't have to, and you would make a horrible spy."
"I have to go, I'm already signed up and I won't go back on my word." John hesitated, then asked, "Can your brother really make it so I never see you again? I need to go to war, but I also don't want to lose you."
"He can try, but if he does he'll regret it."
"I'll come back."
"If you don't I'll come find you and then I'll handcuff us together and make it so no one can unlock it. You'll never be out of my sight again."
"We'll see each other again before I ship out."
"Yes."
"But I have to leave now."
Sherlock didn't answer except to get up. When John was past the door, Sherlock strode over, turned him around, leaned over, and kissed his cheek. "Come back in one piece." He shut the door and leaned against it. Then he looked at the scowling and said, "If he dies, I will destroy the world."