Why did Sai Baba sleep with four lit lamps around him on the hanging plank?

The source material confirms that when Maharaj slept on the suspended plank, he would place four lit lamps at its corners. As described in chapter 0, Nanasaheb Dengle provided a plank to keep Maharaj off the dusty floor of the dilapidated Masjid, but Maharaj chose to hang it from the rafters. The text mentions, "While sleeping, Maharaj would place four lit lamps at the four corners." However, it does not provide an explicit reason for this practice, leaving it as one of the mysterious aspects of the event that drew the curiosity of many onlookers.