There are two such regions in the game, I believe. One you can't cross because it is a hole in the space station's exterior hull and presumably going through it would lead to outer space (though why we can't take the probe to the station's exterior idk). The other is a section of snow where it looks like you should be able to jump up but the game won't let you. If you check the map, you'll see there's no 'door' there, but the rooms are still accessible, just the floor goes all the way to the bottom and stops you from jumping up (I believe)