A sudden rock slide in the Smokies made me triple check my footing now.
I was collecting samples near a ridge in Tennessee when a small shelf gave way, sending a pile of shale down the slope about ten feet from me, so now I always look for loose material and test the ground before stepping close to any outcrop.
Glad you're okay, that's a real wake-up call. I had a similar scare once on a loose scree slope out west. My boot just sank and a whole section started sliding. Now I always kick a toe in first to see if the surface holds. That sound of rocks moving stays with you. Makes you respect the ground under your feet.