# What would an observer see when someone goes through the Turnstile in Tenet?

In the movie Tenet, after the high-speed car chase on the highway, Sator captures the Protagonist and his wife and takes them to a warehouse with a Turnstile. Initially, we are shown a bizarre conversation between Sator on one side of the room and the Protagonist on the other side of the room.

The scene makes more sense when the actual Sator is revealed entering the room the Protagonist is in. The actual Sator then walks towards the Turnstile and emerges from the other side of the Turnstile, where he is inverted and experiences the flow of time in reverse. He then once again has the bizarre conversation with the Protagonist, this time in reverse. So, from Sator's path can be traced using the following diagram.

However, for an observer (like the Protagonist) viewing both the forward and the inverted Sator, he would not see Sator moving in the forward direction on the other side since time is flowing in the opposite direction for the observer. Instead, he would see Sator moving back towards the Turnstile. In other words, he would see

If an observer was looking into the Turnstile at the exact moment the forward and inverse Sator met (at T = 10), what would he see? Would he just see Sator disappear in thin air?

I personally think that he would see Sator vanish, but I can't come up with a good explanation for this. If Sator does indeed vanish, where does he go?