Si Kaojing brought Tan Shuangshuang here just to exchange greetings with the sect leader, and then Si Kaojing arranged for Tan Shuangshuang to sit in the hall with the other practitioners for cultivation, before leaving.
Those practicing in the hall were juniors preparing to explore the Secret Realm. Since they were waiting here, it was naturally because there were still children dependent on family alliances who hadn't been brought over yet.
Not everyone could be like Tan Shuangshuang, having a high-level elder deploy a Flying Heaven Palace to bring them back. It's normal for others to arrive slowly, while Tan Shuangshuang's arrival was the fastest due to Si Kaojing's extraordinarily quick Flying Heaven Palace.
Although everyone was waiting, no one felt impatient, in fact, they even hoped the others would arrive later, much later. The reason was simple: during this time, Sect Leader Wei Tianxiao was giving everyone personal guidance and training.