Orchestra Hall, backstage
The two women standing guard notice the stone and leave to investigate it. To their credit they do leave one of their member standing near the door, but with her attention on her partner's investigation she doesn't notice you slip by her and inside the Orchestra Hall.
You follow the women through the backstage area of the Orchestra Hall unnoticed. Eventually they halt just before the doors leading to the stage of one of the concert halls. With a few quick hand signals the leader orders her troops to position themselves on both sides of the doors where they wait with whips and knives drawn. You realize they are waiting in ambush for someone to come backstage through the doors.
Sunhawk who is onstage doesn't know it yet, but all of the women have readied actions to attack the first person who comes through the doors. I will resolve your action first before Sunhawk's if he decides to go backstage.