Try this add-on to the game: Unreal Mission Pack I: Return To Na Pali
Around the middle of the game, we go into a large technological rooms and go down the elevator to a room with no exits. The game is over with your mod, because to continue the game you need to kill all the monsters in this room and only in this case the platform will rise from the ground. And the player will be able to stand on it and go to another location....
Please make your mod perfect if you can!