So you believe that Matthew, while saying there was more light in the room than he expected, didn't check the window as he went by to his own apartment, especially as he had seen the shutter closed earlier ?
First of all it was pretty dark outside that window. The light from the streetlamps was greatly reduced by the heads of the trees.
It was not in his line of vision as he walked across to middle of the building to join the pathway. In fact it was outside his periferel vision as describe precisely by Heriberto .. our expert. Why should he see it?
You give the impression that Matt walked past the window after he left 5A.
That is not true.
His route was.
1) He left with Russell. They walked restaurant to apartment via the streets and the pathway; Matt to his apartment and Russell to his via the same route.
2. After Matt had checked in his own apartment, he went to Russells apartment
3) Russells little one was poorly so he wasn't returning at that moment. He let Matt out via the back patio doors.
4) Matt walked along the alleyway to 5A and entered at the back via the patio door.
After doing his check, he walked straight back to the restaurant.
He did not go anywhere near the bedroom window. That was on the other side of the building
Soz, Pathfinder but you got it wrong.