Upon receiving information from Chiaki, Leo asked her to send him the data and go to the Capital. He also didn't forget to have Chiaki relay his order to Jack and Shui, who were in Chengdu.
They had to move decisively and catch the remaining members of the Supreme Evil Followers. And this would be the best chance.
The one hiding in the Capital, Eyes, was a tricky one. She was intelligent and cunning, and she knew how to blend in and hide her true self. The mental corruption she spread was also a problem.
Therefore, they needed Chiaki's expertise and her special ability. She was a member of the Mercenary Union, a scientist who studied Qi and its effect on the human body.
Not only that, her Coco could cover a large area someone would normally be unable to reach, and her ability to read and manipulate minds was something no one could beat.
With her at their side, they would have an edge over their enemy.