Convince them you're better, get out, then die. It's easy, just do what you think healthy people do. Talk about the things you would do in your theoretical life, like go to school xyz or get a job in abc or spend time with friends or family. Talk about soccer or some other hobby of yours that you want to go spend time on. Docs love that kind of stuff.
Eat. Eating is a form of self harm to yourself because you hate it so much. Do it even if you hate it, you're going to be dead anyway, right? It will convince them you're better. If you can't eat, tell them you want to do an intensive outpatient on your eating but that you really want to live your life and not be confined in the prisons. Try not to cry, make eye contact, smile even if it's fake, sound neurotypical. Sound very excited for the life you make up and want to live that isn't in the hospital.
It's hard, but you can do it. People are notoriously bad at catching liars despite what they may say. Humans are great liars, if they weren't society would so easily fall apart and scams wouldn't even be possible. You can do it.