Who hides in caves and rocks during the events of Revelation 6?

Les explains that in verse 13 there are cosmic disturbances: the stars of heaven fall, heaven departs as a scroll, and every mountain and island is moved out of place, meaning tremendous earthquake activity. This is only in the first half of the seven years; the second half will be far worse. Even rulers and men in high places are shaken. The kings of the earth, great men, rich men, chief captains, mighty men, every bondman, and free man hide themselves in the dens and rocks of the mountains and actually plead for death. They cry for the rocks to fall on them and hide them from the face of Him who sits on the throne and from the wrath of the Lamb. Les notes that for the last 1900 and some years, mankind has not seen the wrath of God; there has been calamity, earthquake activity, and wars, but that has never been the wrath of God.