The moment that the sound poison flowers were handled by Walker and Gil, every single soldier had rebounded. Not just because the flowers were not forcing their poisonous and impossible to see spores in to their bodies but also because of the purification magic being used.
The healers had been holding on to their mana for the entire time that this expedition was taking place. They had specifically been told to keep themselves held back and allow the rune sewn fabrics and armors to work. Those purification rune patterns had been more than helpful to everyone.
But there was a limit to what they could do. Walker and everyone else had just seen the limit in real time. That monster had been enough to go against the careful planning for general poisons that they had assumed would exist. Not to mention gone against some of the poisons that were outside of what they had imagined.