It's all nonsense. Just calm down and breathe normally.
Then return your seat back and tray table to its full upright position. And make sure your seatbelt is securely fastened and all carry-on luggage is stowed underneath the seat in front of you or in the overhead bins.
Thank you.
These are probably the same people who believe the email telling them that if they talk to strangers in pubs they will be drugged and wake up next morning in a bath of cold water with a note telling them to call this number as their kidneys have been "harvested"....