Can you tell me the story of how Sai Baba saved his devotees from a snake at the Chavadi?

Certainly. In an event described in Chapter 22, Sai Baba was sleeping in his usual spot at the Chavadi, surrounded by light, while his devotees, including Amir Shakkar, slept in the dark outer region. At midnight, Baba began shouting for his devotee Abdul, claiming a 'vivashi' or phantom was near his bedding. He had Abdul search with a lamp and struck the ground with his satka, waking everyone. Amir, understanding Baba's cryptic ways, guessed a real danger was present. He then discovered a large, venomous snake near his own pillow. The snake was killed, and the devotees recognized Baba's shouts as a clever tactic to deliver them from a deadly crisis.