Not that it really matters because I know I am right (lol), but now I feel I have to prove it so, I disagree. It isn't a stair way.
Look at
1m 30s at the video. Remember the set pics, the crashed ship right on the steps of the embassy. The saucer edge had giant door like apertures. The first moment at the link is from right inside one of those openings, looking out. See the wall on the right edge of frame? People are running out of them into the SAME plaza seen from above in the other scene.
The difference between the crash site and the clean version is the passage of TIME. It's been cleaned up since the crash.
Back to the 'louvers', I believe their movement indicate Scotty's presence, if you know what I mean.