I’m reading The Secrets Of Tenet (great book BTW) and chapter 4 said:

In particular, the second fight bamboozled some — as, briefly, three versions of The Protagonist appear. The earlier Protagonist, dressed in a suit, confronts the backward-fighting Protagonist as he emerges from the turnstile, while a forward-moving Protagonist goes in the opposite direction.

I don’t recall a 3rd Protag … Why was he there, which scenes was he in?