The group's aim was not to kill Athena and her companions but to seize the treasures.
Therefore, as long as Athena executed her disguise well, allowing the carriage to continue its journey, those hidden in the shadows would undoubtedly remain unsuspecting of Athena's departure.
They would surely continue to follow, still employing their old methods to deplete Athena and her team's strength.
But why didn't they just take forceful action?
Athena's strength was formidable even by the standards of the entire Alliance.
Even if she wasn't quite at the level of Rick Suleiman and others of his caliber, she wasn't far behind. If she were to fight desperately, she could undoubtedly take many lives with her.
Those with formidable power certainly weren't willing to die here.
They would rather sacrifice numerous lower-level awakened, than put themselves at risk.