Aliens should reduce the territory to neutral after 5 minutes so you only have a short time to 'safe' your territory. It should definitely not be "slowly" ticking down.
If option 3 is implemented how can I ever get close to a target again? Bye bye PVP aspect of the game. I would quit playing.
I seriously don't understand why players would ever pick option 3... It's literally the most extreme option, you should play a different game if that's what you want.