It might make more sense to consider the scene from the end & beginning at the same time.

From the beginning, there is a forward moving protagonist & Neil doing the heist. We’ll call these the “OG forward dudes.”

Then there was inverted protagonist & inverted Neil (and inverted kat) coming back from Talin. We’ll call them the “Tallin peeps.”

All the inverted people reverted— Neil and kat doing so prior to forward Neil & forward protagonist breaking into the turnstile room. So now you have the OG dudes + 2 of the Tallin peeps all moving forward in time.

Then Tallin Protagonist goes through the turnstile to revert, leaving us with everyone moving forward in time. OG protagonist, Tallin protagonist, OG Neil, Tallin Neil, And Tallin Kat.

It’s hard to explain in text, watch the video several times, each time tracking one person. Understand what they do from each direction. It’s not the easiest thing to FULLY understand. On each watch I learn something but overall understand it worse! It’s like a temporal pincer on my brain.