After Piper turns on the strobe lights at P3, she freezes the club to expose the warlocks. At one point, Phoebe kicks a warlock who then falls to the ground. As he falls he knocks into a frozen woman and we can clearly see her move from his fall. However, she does not unfreeze as people usually do throughout the series when someone bumps into a frozen person. In the next scene, we can see that she is still frozen.