Silvia checks out how dark the kid's bedroom is
"This is confirmed in Silvia's statement
http://www.mccannpjfiles.co.uk/PJ/SILVIA_BATISTA.htm"-- The deponent recalls further that she entered the bedroom where Madeleine had been
sleeping. Remembering it now that the door was closed. The interior of the room was dark. The
external blinds were down, light entering [the room] only through the holes in them. The windows
were shut and the curtains were slightly open. Gerry accompanied her on this visit, also with GNR
officers and he said that it had been him who had closed the window because the babies were still
sleeping there, which the deponent noticed to be true. Gerry stated that when he he was told about
Madeleine's disappearance he had found there the window and the blinds open, and the curtains
fluttering [as in the wind]. "
So with the exterior blinds down and the curtains drawn the room is dark when the door is closed.
So for Gerry to see Madeleine the door would need to be open and possibly the shutters up.