She wanted to practice combining some of the arrays. She had always wanted to combine the spirit-gathering array and the protective array but found it challenging.
She had thought that if she could do it, then she could help her soldiers gain access to more and denser spiritual energy to cultivate while in camp and, at the same time, be protected and avoid surprise attacks.
Unfortunately, she didn't have much time to study and could only utilize one array at a time. She chose the spirit gathering array because it would help the soldiers recover faster after each battle.
Now that she had the time, she could study the combination.
She also wanted to explore what was in the forest on the other side of the stream. She felt that her ancestors hadn't just placed the forest there. After absorbing the fog, she had a feeling that there were resources that could help them survive the apocalypse there.