Seems like she was ultimately taking Dante up on that Job Lore earlier cast. Sure, she could change jobs, but the ability didn't work while Chemist was active. Raising her hand to catch the staff as she switched from Chemist to White Mage, the doctor was going to contribute to the attack the best she could and at both Ramaa and Bahamut for making them go through all this nonsense.

> Holy (All Enemies | AOE)
Ancient holy spell. Inflicts severe damage on all targets.