"Yes. Do I need to explain it all to you or can you just pop off the roof like a good little soldier?" Jim asked.
"Give me one reason why I should do what you say." John said firmly.
"How about I give you multiple reasons? First of all, I have my men pointing their weapons at your friends, and they're just waiting for me to give the order. As soon as I give the signal," Jim made a slicing motion across his neck.
"Sherlock?"
"Oh yes. Sherlock, Mrs. Hudson, Molly,"
"Everyone?"
"Everyone. There's no stopping them now."
There was a pause. "Also," Jim added. "If you're thinking of killing me as the only way to save them without you dying, well, that won't work."
"And why not?"
Moriarty leaned in so close to John's face, he was only inches away. "Because." He whispered. John tried to lean back a little. "I have backup and you believe me when I tell you this: They aren't afraid to kill your friends." Jim turned around and walked over to the edge of the roof. "Now can we get this over with already?"
John just stood there for a moment. Then he started to laugh.
"WHAT?" Moriarty yelled. "WHAT DID I MISS?"
"Ah. You're just like Sherlock. You missed the simplest thing." John smiled. "I don't need to kill you. I don't need to die and neither do any of my friends."
Jim smirked. "Oh really?"
"Yes. Really. If I killed you, your men would fire. But they are just waiting for your order. If you don't tell them to kill anyone, they probably won't."
"Well. Wow! I must say that was a smart piece of detective work. And, um, you're right." Jim looked down and held out his hand. "You're right." He nodded. Tentatively, John took his hand and Jim shook it. "So as long as I'm alive you can save your friends. Well good luck with that."
BAM
John fell back in shock just as Moriarty fell to the ground, dead. He had shot himself.
John stared in shock, breathing heavily. After a moment, he slowly walked over to the edge of the building and looked down. He could see Sherlock just coming out of the building. John took a deep, shaky breath and pulled out his phone, dialing Sherlock's number while watching the figure far below answer the phone.
"Hello John?" Sherlock said on the other end of the line.
"Sherlock."
"What? What is it, why are you calling? Where are you?" Sherlock asked as he hailed a cab.
"No no don't do that." John said hurriedly. Sherlock's hand went down.
"Where are you?"
"Stand right where you are, turn around and look up." Sherlock did as John told him.
"Oh my God." He whispered. "What are you doing up there?"
"Nevermind that. Sherlock," John turned to look at Jim's body. "Moriarty, he's um, he's dead. Tell Lestrade to look for three or more men with guns, near Baker Street and in the hospital. "
"How? When? What kind of guns? John I'm coming up,"
"No stay right where you are. Don't move." John was starting to cry.
"Okay okay."
"Listen, I…thank you. For everything. Tell everyone you know, Mrs. Hudson, Molly, Lestrade, tell them thank you. Tell them I'm sorry."
"John what are you doing?!" Sherlock's voice was urgent.
"I'm sorry Sherlock. I have to do this. I have no choice."
"John. Whatever you're about to do DON'T DO IT!" Sherlock's eyes were wide with fear. Actual, cold fear. He was gripping the phone so hard his knuckles were white.
"Goodbye Sherlock."
"Oh God no JOHN!"