At the giving of the Torah, the divine revelation was so complete, permeating all of existence, that no place was concealed from it.
It was so intense that the Israelites’ souls could no longer be contained within their bodily encasements.
When He about whom the verse states, “Man shall not see Me and live,” reveals Himself, it is impossible for a human being to continue living.
When the divine existence is manifest, not only does man cease to exist, but existence as a whole is utterly effaced.
The removal of the concealments and barriers effectuates the immediate nullification of all existences that endured prior within the shadows of creation, leaving only the divine reality to remain.
Rabbi Adin Steinsaltz