The Water Moon Sect is a sect that specializes in developing matrix methods and illusionary arrays and is also skilled at breaking through them, making it a sect with the potential of underground professional careers.
Because they are not adept at fighting, Pang Miaosong's competition with Lu Bei revolves around using matrix methods, which eliminates the need for close combat.
This is what Pang Miaosong meant; she did not want Lu Bei to get close to her in front of everyone.
She would be at a disadvantage.
In all senses of the term.
Lu Bei does not understand the matter of breaking arrays much, even if he has the Array Breaking Compass and mantra, he lacks confidence. However, Heaven blesses those with good intentions, so he had the upper hand over Pang Miaosong. Guided by the compass, he used brute force to overcome the illusionary array.