 CONT: When Mac and Gin are standing on the top of the castles tower  it sometimes has a very low parapet (e. g. when Mac approaches Gin  from behind or when he throws off the glass), sometimes it has a  high embrasure ("I never come up here without dropping something  off"); the position of Mac and Gin to each other changes likewise.  In the first aerial shot from the helicopter, the castle doesnt  seem to have a tower at all.