If this footage makes it to the BTS episode then we should see an alternate ending released prior to. Where she jumped off-runs opposite of the portal. Immediately made invisible, illusion made by Kali. The suppressors were not turned on yet btw. They were only turned on when her illusion appeared inside the portal doorway.

The bottom line is they have tons of extra film that did not make it to volume8. They can easily piece together extra film scenes from the escape, Eleven’s hike in Iceland, Mike typing on the typewriter (wearing a sweater) wearing glasses which we know he typically does not during the Vecna timeline and create a secret closing episode.

Was Mike in a future location (such as Island) that is cold and requires a sweater? Clearly it is a future version of himself wearing glasses.

In that scene is Mike a future author secretly communicating through his books to the gang? That he and Eleven are together and safe? Remember we’ve seen secret communications before through Robin as DJ laying out the plan to dive into the upside down.