At the beginning of the Pontifical Mass, why were the ministers swaying back and forth?
This is the Confiteorof the Mass where the priests and ministers each in turn confess their sins to God. At a Low Mass or Sung Mass (a High Mass), the servers of the Mass slightly turn to the celebrant as they mention him in the confiteorand at the misereatur. But, the celebrant remains still as he bows, confessing his sins. During a Solemn Mass (and Pontifical), the celebrant of the Mass turns to the ministers as he mentions them and the ministers turn to the celebrant as they mention him and turn to him at the misereaturas well.