A/N: This story deals with self-harm, making it possibly triggering. Please be cautious if this story could at all be triggering or upsetting for you. Feedback is always appreciated.

Sherlock was well-versed in sociology. In fact, he was well-versed in most relevant things, though irrelevant details about planets and stars seemed pointless and thus he did not waste his time with them. Sociology, however, proved useful on a daily basis. Did you know, for instance, that a crime happening in broad daylight is unlikely to be stopped by bystanders? If a crowd sees something happening, no one will intervene because all parties involved assume that someone else will. However, if an individual happens to glimpse a crime happening by chance and knows that he or she is the only one to see it, that person is much more likely to take action.

And this is why Sherlock wore short sleeves. Not on days he had fresh gashes, of course, but any time the cuts were past scabs, pink and raised but not terribly fresh, he would make no attempt at covering them. It was, as Sherlock supposed, the easiest way to avoid an intervention. In high school he had kept them covered at all times of course, far away from the meddling eyes of teachers who called school counselors who had worried looks on their faces as they called parents. No, in high school "mandatory reporting" superseded the bystander effect. In college, however, any professor or RA would look the other way, assuming that if he was baring his scars that he was already getting help, and that those who needed to know were already aware. However, should he cover them and someone catch a glimpse they would know that he sought to hide it, and feel the foolish need to act to assuage their conscience. No, really he was doing them all a favor by leaving his scars in the open, unspoken. They felt no responsibility to act when the evidence of his self-loathing was free for all to see.

The first time he had revealed his secret was in the hush of the night, a whispered secret to a friend, a silent plea to tell no one. By the end of the week he had been called into the counselor's office and referred to the "appropriate resources," and asked not to blame his friend, for his friend had spoken up out of concern.

The cuts were better concealed after that day, and he lied his way through therapy, feigning tears at the realization that he deserved better and he was worthy of quitting for his own sake. It felt silly, but the therapist cried with him so he assumed he'd done his job.

Now that could not happen again. As an adult, his parents would not receive notice, nor would Mycroft, and he could walk around campus in broad daylight, knowing that his secret was hidden in plain sight.

The first time he'd walked by his RA, who introduced himself as Greg, but whom Sherlock simply called Lestrade, in short sleeves, he'd watched the man's eyes travel down to his arm briefly. It had been a planned encounter, several days after being on the floor. Had Lestrade seen his scars during their first interaction, it would affect his first impression, but if he waited too long then Lestrade might feel some perceived bond between the two, negating the bystander effect. No, it was far better that it happen within a few days. His plan was working, as Lestrade said nothing. Later in the semester he would occasionally receive, "Are you okay"s from the man, heavy with the words meaning more than what they asked, but he would simply reply with a, "Fine, thanks, and you?" with an accompanying smile, allaying any concern or sense of responsibility on Lestrade's part. Sherlock was an adult, and did not need to waste the time of some college junior put in charge of watching over the freshmen only because he needed free room and board.

By the time second semester came around, Sherlock was fairly secure in the way things were. No professor had said anything to him about his scars, and his family was still blissfully unaware.

There was a small group of acquaintances he had, a variety of students from all social circles who sat at a small table outside the dorms, warmed by the laundry vent, to smoke their cigarettes. They often exchanged pleasantries and many of them spoke about their lives with each other as Sherlock analyzed them in silence, annoyed by how boring most of them were. Still, they were the closest thing he had to friends. Once Molly, a freshman biology major, had grabbed his wrist when everyone else had left. He struggled out of her grasp, but she caught his eyes, and in a more serious tone than he'd ever heard her use, she told him, "I know that you're still doing it and I can tell you're not getting better. They don't notice, but I've been there. I did it for three years. If you ever need to talk, I'm here." His heart was pounding as he smiled politely and thanked her, both of them knowing that he'd never reach out to her to talk.