Disclaimer: I own nothing.
A.N. Prompt is Train Station Goodbye. Not sure how it became this.
It's for a case
"You have to leave London," Sherlock announced abruptly.
"What? But we're on a case!" the doctor protested.
"That's why I need you to go. It won't ever end otherwise," the sleuth declared matter-of-factly.
"Are you saying that I'm being a hindrance? Slowing you down?" John wondered, terrified to hear a yes.
"No, John! It'd never happen," Sherlock reassured hastily.
"Then explain."
"I know who the murderer is," the detective stated.
"You do?" John echoed, surprised. Why hadn't Sherlock told anyone yet?
"Yeah, it's clearly Jones. But he's been so careful that Lestrade would be unable to do anything with that knowledge. I have only logic on my side, and a jury of idiots would never take just my word – or the Inspector's, for that matter," the sleuth explained, annoyance showing in every line of his body.
"What do we do, then?" the doctor inquired, eager for action.
"I provoke our killer and play bait. If he's caught for assaulting me, since the reason of his attack would lie in his other crime, maybe we have a chance," Sherlock replied.
"If you go through with this – and I'd really rather you didn't – I'm certainly not leaving now. I'm not trusting your safety to Greg's squad. What if they are too slow? If something goes pear-shaped? I don't want another flatmate," John declared. He couldn't speak of Sherlock's death, not even as a hypothesis.
"And I promise that you won't need one. But our killer won't make a move if you're around. You've told him of your army past when I sent you to chat with him, and he'll have a healthy fear of you now."
"Well, excuse me if I did. You didn't tell me how I should behave, and he was playing with his father's dogtags. It seemed a reasonable approach. Create some common ground between us, you know," John countered. He didn't want to leave, and didn't appreciate being told it was his own fault he had to in the first place.
"His father beat him regularly," Sherlock revealed, clearly irritated by his friend's blindness.
"How was I supposed to know that?" John protested hotly.
"We're getting sidetracked. I don't want to have a row, John. I only need you to ostensibly leave and make sure Jones knows of your absence, or my plan won't work."
"But why leave London? I mean, can't you provoke him and then we pretend to argue – it won't be hard – so I storm off and return immediately from the back, or something like that?" the doctor proposed.
"If he thinks you might come back at any moment he'll never make a move, John. Especially if he sees you angry. It's obvious. No, we will need to arrange things differently."
John had tried to reason, but there was no way to make Sherlock budge from his decision. And they were doing this to catch a murderer. In the end, they were at Paddington Station, with a large audience.
Their killer was following Sherlock, studying him to plan a move, like they knew he would. Scotland Yard was monitoring the situation. They didn't believe Jones would act in a crowded station, but better safe than sorry. They were so well disguised that John worried maybe they hadn't come, after all. Without telling Sherlock, the doctor had warned Mycroft of the plan, too, and asked him to ensure nothing went wrong, so he assumed at least a couple of the elder Holmes' operatives were around.
"But, John! We're on a case!" Sherlock whined.
John's eye roll was absolutely honest. "You're on a case, and this three days conference will help me with my actual work. I need to keep up to date with the new discoveries in my field. You're a big boy, Sherlock. I'm sure you can take care of yourself." The rehearsed lines still left a bad taste in his mouth.
"Fine then. Go. I'll solve this on my own and not even tell you," the detective replied.
"You know you will. I'll be back soon anyway, no need to pout," John stated, with a put-upon sigh.
"I never do!" Sherlock protested indignantly. Then, more subdued, he added, "Bye, John."
"Bye, Sherlock." The doctor got on the waiting train. The show was at its end.
John would try to get down from his train right then – covertly, of course. Sherlock had asked him to wait until the next station, but he'd try it anyway. In case it wasn't possible without alerting Jones...well, there was Lestrade, and Mycroft. Hopefully that'd be enough to keep his mad flatmate alive.