Cassia successfully  maintains her grasp of the paper, leaving the attentions of the others free to react to the pull of air on their levitating compatriot. When the wind falls the party is whole, waiting outside the arch for Cassia to provide the scroll to the others and for someone to test the mists. The distraction of the wind might have made them miss something, but there was no immediate reaction by the mists to Jin playing with the stone.