Hallucinations, fate or some sort of mania brought on by her brain tumor, she wasn't going to wait for the Grand Canyon.
From an evidential point of view the apparition is the most valuable class of death-warning, inasmuch as recognition is more difficult in the case of an auditory hallucination, even where it takes the form of spoken words; moreover, auditory hallucinations coinciding with deaths may be mere knocks, ringing of bells, &c.; tactile hallucinations are still more difficult of recognition; and the hallucinations of smell which are sometimes found as death-warnings rarely have anything to associate them specially with the dead person.
Parish, Hallucinations and Illusions and Zur Kritik des telepathischen Beweismaterials, and Mrs Sidgwick's refutation in Proc. S.P.R.
Such hallucinations are commonly provoked by crystal-gazing, but auditory hallucinations may be caused by the use of a shell (shell-hearing), and the other senses are occasionally affected.
CRYSTAL - GAZING, or Scrying, the term commonly applied to the induction of visual hallucinations by concentrating the gaze on any clear deep, such as a crystal or a ball of polished rock crystal.