Plot hole: When John is painting the doll's face he looks down at a photo printout of Amanda, you will notice the bruising/scratches on the side of her face in the picture. Please take note of her hair, shirt and overall demeanor. Now think back to the first Saw when Danny Glover had Amanda in the interview room. The picture that John Kramer is looking at is a picture taken of her in "that exact" interview, this is strange however considering that the interview took place after she escaped the jaw splinter, so how does John have a picture of her from the future? (00:51:40)
Plot hole: Out of all of the chains Troy had attached to him, one is hooked to his jaw which is near impossible to do as that would probably kill you and ripping it out would too, which is why Amanda would have placed it there. Jigsaw wouldn't have approved of it, and obviously there's no indication that Amanda had a medical profession, so how did she hook that chain to his jaw and even if she did, without killing him?
Answer: It was too late for Adam to solve the game the way he was intended to- the key went down the drain, which Jigsaw actually didn't intend to happen. Adam's key was meant to be tied around his neck in such a way that neither him nor Lawrence would be able to see, and Adam would be allowed to go free and escape if he were to locate the key- which would only be possible if he looked at himself. The whole idea behind his puzzle was "looking at himself instead of others, for a change." The reason it went down the drain instead, was because of Amanda, who continuously made traps unsolvable. Instead of tying it around him like Jigsaw asked, she just tossed it on his chest, which defeated the whole purpose. Also, he was given a saw just as Lawrence was, as a much more violent plan B, another way he could save his own life.
That doesn't make sense because Jigsaw told Adam that the key is in the bathtub at the end of the movie.