How did Baba use the analogy of the mother tortoise to explain the Guru-disciple relationship?

In Chapter 19, when speaking to a woman who desired a secret instruction, Sai Baba used the analogy of the mother tortoise to explain the nature of a Guru's grace. He told her that his own Guru never gave him a mantra. He then explained that a mother tortoise can be on one bank of a river while her young are on the opposite bank, and she nurtures them entirely through her loving sight alone. This illustrates that a Guru's protection and spiritual nourishment are transmitted through their merciful glance and constant attention, making a formal, spoken 'upadesh' or mantra unnecessary. He advised the woman to simply pay attention to him, implying that this receptive focus is how a disciple receives the Guru's true blessing.