Jian is focusing on perfecting the lightning strike talisman and his disciples are gathering the information from the disciples who had returned from the mortal grade competition. While he was perfecting the talisman he noticed that all life tokens have stopped cracking meaning that they are in stable condition and tokens which have cracks on them have started to resolve themselves.
He Immediately understood that the second trial is over but he couldn't understand why the second trial was for only one day. It should have been for at least a week or more but he also understanding that time difference can be different inside the secret realm. So it is possible that they would have lived inside the secret for more than a day.
At the end of the day very small amount of disciples were returning. He understood that most of the disciples have successfully cleared the second trial.