I mean you may be physically free but mentally captured. For example, you work at a restaurant and you are free to leave whenever you want, but your boss treats you badly. He's always in your head and thoughts because you know that if you don't please him he might fire you and you need your job. Another example could also be that you are physically healthy but mentally ill. For example: You may have multiple personalities and even though you don't have a wounded leg or arm you are internally enslaved to the other personalities which tell you what to do. These are just a few examples of how you can be physically free and at the same mind enslaved.
Romeo and Juliet should have followed Lawrence's plan because it would prevent any more trouble and they would stop having to sneak around everywhere to see each other.
