After Sarah's decision, Nathaniel and his fiancée positioned themselves at their chosen entrance while Kendrick prepared behind his sister.
As soon as both sides were ready, they set out on their chosen paths, not hesitating to go first to show each other that they weren't trying to deceive each other.
Sarah planned to deceive Nathaniel because she knew what the right path was. She was afraid of choosing the right path and raising doubts in the minds of those cultivators that she and her brother were unlikely to win in battle. That's why she preferred the path leading her into a trap.
As for Nathaniel, he didn't think about deceiving Sarah and Kendrick. He was really in doubt between the two paths and had chosen his option to investigate first. When he realized that Sarah had chosen one of the wrong paths, he was a little relieved and at the moment he ran, he only had in mind to go all the way and come back if it was the wrong one.