For what it's worth, i missed it when watching the movie. It just feels like there's something weird that just happened but you can't quite tell, like a nice and subtle spice in a well made dish.

> I do wonder if I'd actually notice just watching it

Almost certainly not; that's the point.

I don't remember whether I noticed it or not when I saw the movie, but I'd like to believe I would have. It reminds be a bit of the final scene of Hitchcock's "Birds":

https://www.youtube.com/watch?v=ULxw4UDY5g8 (up until 0:35)

1. What reminds you of Birds? I don't see the parallels.

2. The original Birds did not have that music. I cannot believe how classic media remasters completely ruin the tone of the originals. From Star Wars, to Rust in Peace, to Birds now.

The parallel is not obvious because no mirror is involved. It is the fact that camera is moving backwards in front of the actors who approach a closed door. Then Rod Taylor reaches for the handle and opens the door and the outside light shines in.

How come the camera is not in the way at that point? Did it move backwards to the closed door? The answer is quite interesting. Let me know if you'd like me to spoiler it for you.

I remember being surprised by the effect, and totally unsure how they pulled it off. Positioning the camera in exactly the right angle to match what the moving camera was shooting? I can't even picture it. Impressive work!