So, I guess the easiest way to fix the exterior/interior lattice problem is delete the structure on top of the exterior shot so the top is just flat, as one of the mockups showed.

And I hate to question you Ady, but are you sure that's where the window is:

I mean, the lighting must be all kinds of messed up since the shadows are on the back wall at the beginning, and now on the front or side?

EDIT: It looks like the corridor appeared along the back wall. If you look at the shadows across the wall decor, they match perfectly with the establishing shot. Maybe just insert that corridor in the first shot?