Sherlock stared after John as he grieved. He never knew he meant so much to John. Maybe because he was so busy trying to figure out his own feelings that he didn't have time to deduce John's. He thought back to the first time they were having dinner together at Angelo's. That time that he thought John was asking, and a time before he started hoping. The first time they ran all the way back to Baker Street. The first time John had made him laugh. No one had ever made him laugh before. He only ever faked it, to get information. But John, wonderful, amazing, John could make him do anything. John could make him eat, even when there was an important case. John could make him smile and mean it. John could make him sad. John could make him feel. Snapping back to the present, he saw John limp away with his crutch. Sherlock winced at the sight of that thing. That thing symbolised that John was hurt. Sherlock never wanted to see John hurt or in pain. He didn't like. That's why he tried to get rid of it all that time ago, even if he didn't know why at the time. He saw John catch a cab with Mrs Hudson and had to bite his scream back. He desperately wanted to be able to hold John, tell him it was alright and tell him that he loves him, but he also wanted John to be alive and there was a very fine line between the two.
Sherlock stared after the cab and used every ounce of willpower to not run after it. He waited until it was out of his car and walked over to his tombstone. He hated it. He wouldn't mind being dead, if he didn't have John. But he hated that stupid slab of cold stone. It had hurt John. But no, the tombstone hadn't. Sherlock had. And he would have to live with that for the rest of his life. He sighed and slowly made his way back to Molly's car and they made the drive back to her flat. When they arrived, Sherlock grabbed the clothes she had offered him and got changed. He came out of the room with his best weapons in his pockets, and went to say a quick goodbye to Molly. A quick goodbye which did not go as planned.
"Sherlock, you don't have to do this."
"I believe that I have tediously explained this many times."
"Sherlock-"
"I HAVE TO DO THIS! THEY WILL STILL FOLLOW ORDERS EVEN WHEN MORIARTY IS DEAD!" When he saw that she looked frightened, he closed his eyes and took a deep breath
"Don't you see?" He said quietly "I have to kill them, or they're going to kill him."
"You love him, don't you." Molly said defeatedly as she looked into his eyes. Eyes filled with pain, confirming everything she already knew. It was never really a question.
"Goodbye, Molly Hooper. Thank you." He kissed her on the cheek and walked out the door. She looked around her once again empty apartment. 'They always leave.' She thought sadly 'Always.'
Sherlock was almost unrecognisable in a hoodie, jeans and sneakers as he walked around London. He would be able to tell which people worked for Moriarty. They were the ones who were looking for him as much as he was looking for them. The first five were very easy. They were all sitting round at a cafe and boasting about which one had done more for Moriarty, which one would've had the honour of killing John. Their conversation fuelled his anger, it was everything he could do to not walk up to them and snap their necks. Instead, he managed to slip strychnine in their coffees when they weren't looking. Five less threats to John down, ninety-five to go. 'I will do this, John. I will kill them all. You will be alive. I will do this.'