Other mistake: In the cave, Angélica steps out of the water and in the close-up of her face her hair is dry, and even drier in the following close-up.
Other mistake: In the mutiny scene where the cook is torched, the distance between the long boat and the Queen Anne's Revenge increases when the cook is only shown paddling away after the QAR turns towards it.
Chosen answer: She most likely went to stop the ritual, she probably didn't want her tear to be used by the likes of Blackbeard. She knew that Jack would use it wisely.