This is shorter guys, hopefully that's ok
Sherlock was pacing back and forth in the flat, wringing his hands. He glanced at the clock. 3:47 am. He ran a hand through his hair with frustration as his mind rebelled furiously under the extreme pressure of absolute quiet. His mind raced over the case for the hundredth time, reviewing the victim and killer in his mind, lining up all the possible outcomes and connections. He was about to wake John when he heard a noise from downstairs, footsteps and the front door opening. The downstairs neighbors had been making noise until two, but then it had seemingly gone quiet, assumingly all the inebriated teenagers had dropped off into a slobbery slumber. He dashed to the window and peeked out the curtain.
There she was again. He peered out, trying to make out a single discriminating factor that would give the mysterious shadow of a girl away. She appeared startlingly slender in the darkness as she lit a cigarette-good god, how many was that today, two packs?-not like cared anyways, he would've been smoking himself if it weren't for the blasted inconvenience. She still wore nothing but the dark, tattered dress, but did not appear cold. How? It was January? His mind raced through the possibility of a disease debilitating nerves to the epidermis, but quickly eliminated it, there would need to be some sign of injury, and due to the amount of skin exposed he had seen no visible scars. He leaned in a little closer, his breath briefly clouding his view as it fogged the window.
"What are you doing?" He hissed into the darkness.
Almost on cue, as if she had heard, she looked back and saw Sherlock in the window. Stoic and nonchalant as ever she barely flinched at the recognition of being watched. The sylphlike face cocked to the side and he barely made out a little smile before she slipped off her shoes and placed them on the front stoop right next to the railing. She gave one backward glance up towards him and smiled before turning around, and with the grace of deer, she lithely leapt from the stoop into the empty streets, sprinting into darkness. He watched as the night shadows swallowed the slender figure.
He retreated from the window and returned to the placid flat. His eyes flicked over the books, all read and devoured, the newspapers and open laptop that promised no new cases at this ungodly hour. Frustrated and tense with the lack of stimulation he grunted disgustedly before throwing himself into the chair, legs folded up petulantly.
She had seen him, after all, recognized him, what about the smile, was that meant to be mocking? Who cared, she was just his neighbor. Or his latest case. Hah. Sherlock snorted out loud at this. Silence thundered in response. The clock ticked by, marking the passing of each second with honorable diligence. The tap must have been leaking, he could hear the drip from the kitchen, it was at least three seconds faster than it had been in previous nights-
"Right" He shot up to his feet and grabbed his coat. No cases, no experiments, no mass murderers, no terrorist plots-there was but one thing left to soothe the ache in his rotting mind.
He grabbed a scarf before bounding out the door and taking off in the direction of his strange new neighbor.