What were the FA doing?
From the passenger video from post #154, it appears that the FA were handing out trays and serving drinks rather than clearing up - see about 40 seconds in for a tray being handed to seat D or E. There is also a shot that seems to show a coffee pot being wielded.
This was all happening after the "plunge", as the seat-back display shows altitude 10002 feet and ground speed 348 miles per hour. Another video in the same set shows the seat C passenger still with a tray and altitude going down through abot 9500 feet.
With the order of an hour to go to Manilla and things more or less stable, it seems reasonable that the cabin crew should maintain normal service. That would give everyone less time to worry!