I would say to them:
You are caught in the middle of an 8.5 magnitude earthquake.
Nothing you did (or could have done!) had any part in bringing
this about.......but your decision stream past this point will
determine your survival probabilities.
Do not be one of the unfortunates who freeze in terror.
Do not be the one stuck in a loop thinking "this is'nt happening"
It IS happening.
Act. Now. With the knowledge that many, many people will be killed
by this event----make the survivors choice that YOU won't be one of
them......and go find a doorframe to brace yourself in.