Another one of those experiences I've always wanted to do.
I can well imagine the freedom and power and self control/discipline required... what a brilliant challenge!
AFTERWARD: well I finally did it! ~bounce~ Probably one of the most amazing sensations... actually on the same day I walked on broken glass too, astonishing again and utterly different. With the firewalk it was all about getting yourself mentally equipped, psyched up and just walking calmly but firmly/reasonably swiftly through the coals/embers. Amazing! Totally all about 'feel the fear and do it anyway'.
With the glass walk, it was all about calm, assured focus, total concentration with no room for distraction. That was REAL broken glass, not sugar glass, actual smashed up bottles with jagged edges pointing up and everything!
So for me, the main lesson? It was more personally 'empowering' to walk over broken glass, where it was all about my skill/self knowledge/focus... than the firewalk, which although utterly amazing, was more about getting across it without getting burnt!