How can anyone give the command "Brace X 3" if this is not a planned crash landing.
Stay on course report on the facts don't speculate
Airlines have standardized communications (public address and non-verbal). Those signal(s) are not always, "BRACE BRACE BRACE".
Properly trained Flight Attendants will initiate brace commands when cabin conditions present; with or without said signals from the F/D.
Stay on course, report the facts?!
Go away.