Wicked men and women use the forces of earthly government to fortify themselves like kings against harm, financially and physically. Trapping them together inside a mountain city seems like a foretaste of Hell.
The Godless reprobate Globalists who are bringing on the Four Horsemen of the Apocalypse will indeed be trying to hide in the mountains. It will do them no good:
Revelation 6:15-17
King James Version
15 And the kings of the earth, and the great men, and the rich men, and the chief captains, and the mighty men, and every bondman, and every free man, hid themselves in the dens and in the rocks of the mountains;
16 And said to the mountains and rocks, Fall on us, and hide us from the face of him that sitteth on the throne, and from the wrath of the Lamb:
17 For the great day of his wrath is come; and who shall be able to stand?