I know that smoke grenades affect soldiers' defense when they stand in the area while being shot at by the enemy during the enemy's turn, and are affected by thin men poison clouds if they stand in the area.
However, do smoke grenades or poison clouds affect soldiers in the middle of a move or turn? e.g., if I wish to run a soldier from point A through point B and finish on point C, and I suspect that he will trigger an alien overwatch as he runs through point B, will a smoke grenade on point B protect him? If a soldier runs through a poison cloud but does not start or end the turn in the cloud, will he become poisoned?