So how about a Sherlock with a little cross section of Person of interest involved? Weird idea, I know, but it's been hopping around my head for a while. Definitely AU.
Molly always knew bad code before she had even spoken to them. The foulness of humanity made it particularly easy. There were good people—good code-nice citizens who really didn't want to injure other people, except in the defense of their own family. Then there were bad people—bad code—who needed to be deleted. Child molesters, rapists, men and women who thought they could play games with people's lives on the line, murderers who slipped through the cracks, and liars. She hated them. There was so much bad code in the world, so many numbers that the world could go without. When Harold Finch came up with The Machine, she was right there in the background, waiting, watching. Root gave her most of the access she needed, allowing her to perform her own form of vigilantism. Separating good and bad code was usually easy.
This was, at least, until she met Sherlock Holmes.
Actually she saw his number six months before she actually met him. She found a man too smart for his own good, trying to shoot himself up into oblivion and dismissed him as bad code. But then, four months in, his number came up again, and he had saved a small child. He was clean for three months when he first walked into her laboratory as she was on the computer, spouting a great amount of data about her before turning around and using one of the microscopes, an apologetic DI Lestrade following close at his heels. Good code. Bad code. When she really did the math, she found that Sherlock was equally good code and bad code, a 50.000001% split. That tiny one at the end was good code, and thus she allowed him to stay, despite being almost a greater anomaly than a red haired woman in New York City who was 99.99999% good code. This made him fun to observe through the cameras in her free time, when she wasn't sending information in the direction of NSY.
When John Watson first came into the picture, there was no marked change. However, what she found most fascinating about the man was how slowly that one turned to a two, to a three, to even a four. She found this observation even more fascinating in the fact that she got to witness more than snapshots of it, as the pair were more or less involved in Molly's work life. She knew that there was nothing else she could do with the anomaly but perhaps perform a few experiments. What would he do with a woman who adored him? Who stuttered and tittered about? Ignored. That was easy, but it was a fun game to play, a nice habit to get into.
Then she met Jim Moriarty—Bad Code. Very, very, very bad code. He needed to be deleted.