A World God Is A Money Maker.

She knew it was an involuntary act on Mihila's part but it always made Kayla mentally unstable. Even though she knew Mihila won't hurt her, the mana around her has changed that certainty to probably. It was telling her that she may not be hurt intentionally, but anything could happen unintentionally. It is not a good thing to be around someone that might probably hurt you and that person is playing around with a dangerous weapon. 

The knowledge that you are this close to highly fatal damage makes it difficult to simply relax and mingle. She becomes mentally exhausted by the time she leaves Mihila's presence. So chose to stay outside the building while Mihila brought the kids for identification and confirmation.