This is a precursor to Revelation 6, where the elites hide out in bunkers; what this time and that have in common is that they take all their employees with them wherever they go. "Everyone" means "all kinds of people", not literally "every person". This could explain those numbers:

Then the kings of the earth and the great ones and the generals and the rich and the powerful, and everyone, slave and free, hid themselves in the caves and among the rocks of the mountains, calling to the mountains and rocks, “Fall on us and hide us from the face of him who is seated on the throne, and from the wrath of the Lamb, for the great day of their wrath has come, and who can stand?”