I was questioning Jamie's parents. At 13, why was he out at 9.30/10pm. Did the parents know where he was? Was this the norm for him - being left to his own devices?
Dad was often absent, but this was because of work, but I wonder how the lack of having his dad around shaped Jamie's behaviours.
I thought Jamie's behaviour with the physiologist showed how short a temper he had, and that it could have been "red mist" that led him to attack Katie, and the other boy in the "prison", as shown on the CCTV. Red mist being a reason, not an excuse.
Overall it was a really well told story, and the acting was amazing, and (echoing everyone else) especially the actor playing Jamie.