"Now stay still and don't move a muscle." Jim whispered. Sherlock looked at him flatly.
"Diaphragm." He said blandly. Jim blinked.
"Pardon?"
"My diaphragm. It's moving because I'm breathing." Sherlock said snidely. "If you're going to make nuance threats then we'll just be on our way." He spun around. "John, Madeline; let's go h-"He toppled forwards with a bang to showcase Jim standing behind him and pocketing his pistol with a sorrowful look, like he'd shot his favorite dog. Madeline made a strangled gagging sound, and John shouted something between "no" and "oh".
"You and your need to always have the last word." Jim said, staring down at the detective's motionless body. "In a way I saved you. Got the parasite that's been latched onto you for years by removing the host." He glared at John and Madeline, who were motionless and absolutely shell-shocked.
"Look what you forced me to do!" He demanded suddenly, pointing down at Sherlock, whose blood was leaking steadily from underneath his curls. John wanted desperately to run to his friend and inspect the wound, maybe staunch the bleeding; but he knew there was nothing he could do, even if Jim let him get close to Sherlock's body. Madeline's mouth kept opening and closing like a fish, and she watched Sherlock's blood leave his body until it touched the tips of Moriarty's brogue shoes a mere foot away.
"Now there's just one loose end to tie up- the parasites." Moriarty spat, swinging the gun around to face Madeline and John. They didn't have time to move before a gunshot made John numb. He watched in horror as Madeline wrapped her arms around her stomach in a futile effort to hold the blood from Jim's bullet wound in. Red leaked between her fingers and riveted down her body as she slowly keeled over onto the floor, heaving.
"Oh dear, seems the little damsel has fallen." Jim mused. John stared at her body, then at Sherlock's. Then he could finally move again. He stormed forward, with his head low and his hands balled into fists, ready to fight and throw as many punches as needed. Jim saw him coming from miles away and had plenty of time to heft his gun and aim it between John's eyes. He instinctually halted and made sure to stare Moriarty down. He was outgunned and terrified, but there was no way in hell he'd let the bastard know. Jim smirked and slowly lowered the gun until it was level with John's breast. The doctor brazenly stepped forward a so that the muzzle was pressed uncomfortably against his chest.
"Do it." He challenged. "I dare you to actually do it." Jim gave him an amused but mocking look and rolled his eyes to Madeline and Sherlock's bodies on the floor. Any hope John had had of saving either of them was long gone, Madeline had stopped moving, and lay motionless as her blood stained the concrete and just barely mingled with Sherlock's. The detective still didn't move, despite John's fervent hopes that he would spring up with some clever way around the truth and save the day. He dragged his eyes back to Jim.
"Do it." He growled. The criminal gave him a simpering look.
"I'll be sure to let Mary and your baby know the good news." He said lowly, pushing the gun muzzle harder against John's chest and slowly tightening the trigger as the doctor's eyes widened at the thought of his new family.
"No, wai-!" There was a muffled crack from the sound of the bullet entering John's chest and punching through layers of fat, bone, muscle, and tissue before he collapsed to the ground beside Madeline and Sherlock, dead. Jim huffed and waved the gun in the air to disperse the smoke leaking from the barrel just a bit, then he hurled it into the depths of the car park with an angry roar. He grimaced at Sherlock's body, motionless under the halogen light; and fought the urge to kick Madeline and John's bodies where they lay mere feet away from each other. After a good bit of ranting to the silence around him Moriarty composed himself. He raked his hand back through his hair in an attempt to slick it back again and brushed his suit off to the best of his ability. He cast one more look at the three bodies on the floor, his own handiwork, before curling his lip, leaving the car park, and disappearing into London in search of a new "toy".