Even before Tim had a "chat" with Cory, she started acting a little different. She was sullen, but more than that, she was reserved. The fire was gone, or at least hidden. It all started after the furious assault on Drake and its utter failure. While she may or may not have been justified in her animosity to the sweater guy, she most certainly overreacted. His glib comment had been the final straw, the small change that caused her to erupt in anger. She accepted Saul's condolences, but did not take him up on his offer for cathartic conversation. Just the acceptance part itself was out of character.
It was an emotional state that had been growing. So when Tim did give her a warning, she accepted it without rebuttal or anger. She actually accept the censure. What she didn't talk about though is that Tim was not the only one to have chastised her for her behavior. As her attacks failed against Drake, she felt Sun and Moon pulling away, leaving her empty.
That first night, and several after instead of sleeping, she meditated. She took off all her armor, laid down all her weapons (all two, but still), and sat in the open by a small fire. She did not raise her head to the sky, but her heart and her spirit soared into the heavens as she prayed. Even in her trance-like state, the first night, an observer would have seen Cory shake and cry, emitting a quiet whimper. Her vision started with an eclipse. Whatever the scientific reason for an eclipse, or whatever other cultures ascribe to it, for Cory, it meant the absence of both Sun and Moon. It was a moment where she was absolutely cut off from their power. Physically impossible or not, it was Moon which reappeared first.
The message was clear. Cory had become imbalanced. Her use of Sun's powers had not been for the good of life, she had not fulfilled her mandate to protect the weak and contain the strong. The only reason, and she knew this as if it had been written on parchment laid at her feet, she had not been stripped of her power totally was that she protected her friends without fail, and she was an effective fighter against the truly hellish creatures she encountered. Her faith was a powerful weapon. She was straying from the path set before her by Sun and Moon.
Now it was Moon's turn to lead her. Cory could take up her arms, but until she had paid her penance, could only use them for defense. No magic attacks, no fighting, only defense.
The others maybe did not understand. She tried to explain to Tim. Maybe he understood, maybe he didn't, but she had two options, choose Sun and Moon's path, or leave the path all together. Maybe he'd understand it that way.
One positive note about the whole situation was the teachable moment for Merl. She explained to him about her powers, about her devotion to the deities of Sun and Moon. She didn't describe it as a religion, but a personal faith. Describing the specifics was challenging, since Cory didn't talk about it much, and it was almost purely "feelings" without words. She never made excuses to Merl, only described where she failed to live up to the standards she tried to live by. The standards that she must live by to continue to serve Sun and Moon.
So during the trek, mission, whatever, Cory was not on the front lines blasting away. It was very hard for her to do. Very hard. Maybe that was part of the point, she hadn't been so angry and prone to violence when she first gained her powers. But as she grew in strength, she had gravitated towards Sun's powers, and perhaps gone too far. But she was capable of healing people, of creating illusions to help distract enemies, helping communicate instantly between groups, and using the powers of her armor to teleport or speed around as needed. She could still help, she did still help, but not with enormous gouts of flame. She could do other things too, driving when needed, piloting something when necessary, and cracking the odd computer security system. She could shape change and scout ahead, or behind, or the flanks. She did this when Tim wanted more intel on enemy movements. She even offered to take one of the convoy vehicles to get an ammo resupply, but she knew Tim would veto that idea. There were a surprising number of other ways for her to help, probably Moon's point.
Still, it was hard.