According to the Diary Card’s Hint…

The moment that the information recorded on Lin Sanjiu's Diary Card integrated into her consciousness, Mrs. Manas understood all its content as she was part of Lin Sanjiu's [School of Higher Consciousness]. Before Mrs. Manas could ask Lin Sanjiu what was wrong, she immediately changed her words and uttered, "Hurry! Go back!"

Even without Mrs. Manas urging her, Lin Sanjiu had already broken a window along the corridor and got out of the building. She flew upward as fast as she could but she was still too late. When she reached the "15th" floor upstairs, the siblings standing at the entrance of the stairways had disappeared.

"Damn it!" Lin Sanjiu cursed in her mind. She drifted hopelessly around the corridor a few rounds, but as expected, she couldn't find a single trace of the siblings.