I think yr correct there to some degree "fliegenmong" (goota explain that name sometime!:)) there was such an event, not sure of the details tho. I think the flight crew in such a hypothetical case could wonder back into the cabin & get the lattest update of their fate !:} Nothing would surprise me these days !
"Airtags" I wonder how many actually swipe their credit cards to watch anything? On a short flight such as syd -cb you wouldn't have gotten enough value for yr swipe...............but ML-SY some times you could watch the movie "dances with wolves"(long movie) several times over whilst ATC deal you out from the stack !:}

CW

I think when there is a total power failure on board the IFE stops working too, But it would be unlikely that the IFE system was working in the first place. That was outsourced years ago.