forever and ever
You don't. [He never considers the switch strange, he's just usually thankful when Birdman doesn't think that he has to intimidate him at the moment. It is way more pleasant to deal with.]
That is part of how and why it is a prison. It is very pleasant here, but there is no way to teleport out- we are too far under water.
[Cain has been sitting rod-straight this entire time. A mixture of too excited and the uneasiness he can't always pinpoint in his stomach]
Our thoughts and actions are monitored by Sentience, so even if we tried to go into the stabilizer and try to make it do what we wanted it to, there would be no guarantee that we would not just die in the process. Not that that is a particularly big deal, but there are easier ways to kill ourselves.
And the most important part that you have missed is that we were switched on our way out. Sentience has replaced us with doppelgangers that will no longer commit crimes. I am not entirely sure how that is supposed to work, or if it is true since there is no way to really verify, but if it is a lie, it is a very consistent one.
No way out. No one notices we're gone. The whole point of this is that we rehabilitate or die here.