This is in reply to your 12/29 post What happens to them?  Although I don't know all the answers to your questions in your post, it is the angels who sever the wicked from the just at the end of the world according to Matt. 13:37- 43 when the tares are separated from the wheat, and according to Matt. 13:47-50 when the bad fish are separated from the good fish with the wicked being cast into a furnace of fire by the angels.  The furnace of fire may very well be the lake of fire because when the goats are separated from the sheep at the Sheep & Goat judgment in Matt. 25:31-46, the goats go away into everlasting punishment which would be the lake of fire and the righteous go into life eternal. It would be everlasting punishment to be tormented day and night in the fire and get no rest as shown in Rev. 14:9-11.

As for anyone hiding out in underground caves and dens, I don't think it sounds like they have repented because they want the rocks to fall on them according to Rev. 6:15-17,  "And the kings of the earth, and the great men, and the rich 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: 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; For the great day of his wrath is come; and who shall be able to stand?"  They don't sound repentant; they sound guilty and fear the wrath of the Lamb, Jesus Christ.