"Be ready to use your movement technique anytime as I can tell some of those Monsters would escape. We need to kill those Monsters in any condition so that we can complete the mission."
Livia already commands her 2 teammates. Even though they could see 15 Monsters in front of them, you cannot become sure that you would be able to kill all of those Monsters at once.
First of all those Monsters have quick response speed and also even though all the warriors sure that those Monsters did not notice them, there is a chance that before any attack to reach them those Monsters would escape from that place.
She told that to her teammates using telepathy. Fortunately her second team already noticed them. With this they will not get startled. This is the reason that Livia already told her other 2 teammates to be ready to use the movement technique anytime.
