How did Sai Baba prove his omniscience to Laxmichand through the incident involving a cough?

Sai Baba demonstrated his ability to know a person's innermost thoughts in a remarkable incident with Laxmichand. As Chapter 28 recounts, Laxmichand saw Baba coughing during the Chavadi procession and privately thought to himself that it might be the effect of an 'evil eye'. This was a fleeting, internal thought. However, the very next morning in the masjid, Baba openly voiced the exact same idea, asking Madhavrao, "is this the effect of an evil eye?" Hearing Baba echo his own secret thought left Laxmichand in wonder, confirming for him that Baba dwells in everyone's heart and is aware of all things, even silent mental impressions.