What triggered Sai Baba's sudden and terrifying anger, causing Him to assume a 'Narasimha avatar' at the Masjid?

The incident, as described in Chapter 13, was triggered by the commencement of paving work in the Masjid courtyard. Baba had given permission for the work to start after His return from the Lendi. However, at the very first sound of a pickaxe striking the ground in the area where the chariot used to be kept, Baba had a strange and furious reaction. His eyes glared terrifyingly as He assumed what appeared to be the Narasimha avatar. He grabbed his Satka (stick) and shouted, "Who is striking the pickaxe? I will hang him by his waist!", which caused the laborer and others present to flee in fear.