C196 A Missed Secret

Is there a way to make stones rub together without making any sound? The stones weren't light, so logically, the noise should have been louder. Yet, oddly enough, Yoshikawa didn't hear a peep, as if nothing had occurred at all. But what unfolded before Yoshikawa couldn't possibly be nothing; it must have been something significant!

The corner was well-lit, both inside and out