I m not sure you understood what he said.. Of course the player has no option the make MC and Heather leave the estate, but in the story they are not forced to stayFree to leave really !!!! Did you see any dialogue or an option to be able to leave, all your stuff is locked in a safe, phone and such.
You have no way to access to the outside world and there is no option to go ask the Mistress to leave.
I guess that you are dreaming my friend, you just do not want to aknowledge that you are trapped because you are to afraid to admit it !
That one principle of controlling people, let them dream they can leave, even if the can't, so you can control them better.