Continuity mistake: While George Foyet is stabbing Agent Hotchner, the knife is extending from the handle. The blood is at the top of the blade, and as he removes it, the blood moves to the bottom of the blade, while the top remains clean.
Continuity mistake: In the scene where the unsub is having a tea party with her "dolls", look at the diabetic woman's right hand when the unsub is pouring her tea. When the tea is being poured the doll's right hand is palm up. When the camera cuts to a close up of the cup the doll's hand is face down. The doll is paralyzed due to the drugs and had not regained control of her body yet, making it impossible for her to move the hand on her own.
Continuity mistake: At the end a shot is shown of the FBI airplane in mid air. The airplane shown is a Gulf Stream V; which has a very distinctive nose. After the scene inside the airplane; another shot is shown of the plane's exterior, however all of a sudden they fly a Gulf Stream 100, which is a significantly larger plane and a very different design. (00:41:05 - 00:45:00)
Answer: "The Boogeyman", s02e06. Spoiler alert: The kid is Jeffrey Charles and at that point he had already killed 3 other kids. Jefferey basically hated and resented other kids after his mother abandoned him and his father spent a lot of time with other children because of her job. Jeffery would lure kids Into the Woods and then beat them to death with his bat just because of hate, no particular "reason." The scene you're describing, Jefferey agrees to walk Tracy home when her "buddy" leaves her (at this point the FBI announced there's a serial killer on the loose and kids should walk with a buddy). Jeffrey gets mad at Tracy for walking too slow and for complaining, and he takes a swing at her, causing her to flee Into the Woods and have Jeffery chase her.
Bishop73