Mo Lingxue has always been and will always be a careful individual. During her times as one of the sect masters of the Valley of Harmony, it is exactly this carefulness that leads her into multiple victories and success on things that will be beneficial for the sect, being crowned as one of the sect masters who contributed most to the sect, someone nearly on par with their founding ancestors.
That is why the immediate thought that appears in her mind as she heard the voice in her head are these two: first, she's going crazy from the longing towards her daughter, so much that this issue created a mental demon in her heart, and she needs to deal with it as soon as possible and the second one is that there's a powerful entity projecting this thought to her, perhaps as some sort of trap to lure her in somewhere else.