Jacob's words were like a bomb in everyone's mind because Jacob directly hit the nail when he tempted them with the location of the legendary key.
Jacob knew the entire unique plains were stirring because of the missing legendary key. As the opening time of the path of legend was drawing near, the hidden experts who were eying a higher realm of power would naturally not sit still.
His conjecture became more solid after he learned that so many Quasi Legends were suddenly making moves. Although revealing the clues about the legendary key would put him at huge risk, he was now confident in escaping with his life from any kind of threat in the Unique Plains.
Moreover, the purpose of only revealing the part about how he knew where the legendary key was but not that he already had it put a layer of protection on him. If they wanted the legendary key, they wouldn't make a move until they didn't want to lose their only lead.
