It is hard as the whole house is shaking violently.  As Susan fellows your instructions.  Grabbing the robe you toss her and running out to the deck area.   Just as she steps out onto the deck.  It gives away, brought down by the ground shaking.  She just manages to turn and grab the threshold of the doorway.  To keep from falling with the deck down the side of the slope.   The robe goes falling as she lets go to grab.