I watched the scene in Prisoners where Bob Taylor supposedly breaks into the Dovers' house carefully. When he gets into the children's room, Mrs. Dover comes right after him but then he mysteriously leaves the house through the bedroom window. How did he get out? It just isn't possible.
We see him enter Anna's room at which point Mrs. Dover is awoken by a noise. The camera pans to her for approximately 20 seconds before she gets up and goes to investigate, more than enough time for him to grab some clothing and leave Anna's room and hide somewhere.
There are two other doors in the hallway in between Anna's room and the master bedroom, a bathroom and probably a closet. He hides in the bathroom and waits for Mrs Dover to run into Anna's room, and then leaves via the master bedroom window. We can even see that the bathroom door which was closed at first is later opened.