Fair enough but to find answers we've got to ask the right questions. Why would an abductor take the risk in opening a window and shutters? It doesn't make sense. The only possible reason I can think of would be that he was passing Madeleine through the window to someone else but it was quicker to go in and out through the door. He had to squeeze past 2 cots then bed and chair in corner and left no window evidence.
Can we really predict why people do things?
Maybe he felt threatened by the patio door visitors while being in the room.
Maybe waiting for accomplice?
Maybe this person who was in was not the person who actually took Madeleine away?
If I want to be really nasty I can even say that it could have been Matt Oldfield who opened that window and who passed Madeleine through it to someone as he had the most of the opportunity.
I think the PJ thought that on the beginning. It was written somewhere, I think the Guardian that he was given the hard time due to being last before Kate found Madeleine missing and obviously being the one who offered to check.
This is just an example.
It can also be a member of personnel of OC club who 'agreed' to enter the apartment and take the girl out.
It could have been a local petty thief who woke up Madeleine and accidental killed her by making her quiet so she would not scream.
Opportunity, organised it can also be an accidental situation. We don't know, but we can at least hope the police is on their track.