According to Chapter 10, what was Sai Baba's sleeping arrangement and what was mysterious about it?

Chapter 10 describes Sai Baba's unique and mysterious sleeping arrangement in the mosque. He would sleep on a narrow wooden plank, only a span wide and four cubits long, which was hung from the rafters by old rags, much like a swing. Lamps would burn at his head and feet. As this chapter highlights, the most mysterious aspect was that his movements were imperceptible; no one ever knew when he climbed up onto the plank or when he descended from it. This seemingly impossible feat pointed towards his divine nature and powers.