What impact might an event or detail from this chapter have on the future of the story?

Percy overhears the following conversation between Grover and Mr. Brunner:

"But he may not have time. The summer solstice deadline" Mr. Brunner, "the Mist over the students and staff will be enough to convince him" (that he never saw or knew Mrs. Dodds ).

This foreshadows that all is not what it seems for Percy.