The two Dashavatara dashed into the Royal Castle of Ress despite the fact that Matsya wanted the Dashavatara to work together. He opened this telepathy consult to have better coordination among the armies and pull a decisive blow against the humans. However, the other Celestial Avatars also felt the same way that they should just aim for the boss, just as how the Rifle Mages had aimed for them.
Yet at the same time, their armies needed them to ensure their survival and if they did not keep the rank and file busy, the humans would definitely make things difficult for the group. They would continue to target the Celestial Avatars especially when the Dashavatara do not have any idea how to remove this so called poisonous effect.