I think the song's about always putting a wall between you and the world, being defensive and not letting people see the real 'you'. But there's a desire within you to get to know people better and have them know the real you and not the 'pantomime' you perform for the public, but being too insecure or afraid to do so. So you want others to show themselves to you while you still keep your true self hidden away from the world, like a two-way mirror; you can see them, but they can't see you - perhaps they only think they can but you know better... and in a way it's killing you inside to not be able to let your guard down.
I think the song's about always putting a wall between you and the world, being defensive and not letting people see the real 'you'. But there's a desire within you to get to know people better and have them know the real you and not the 'pantomime' you perform for the public, but being too insecure or afraid to do so. So you want others to show themselves to you while you still keep your true self hidden away from the world, like a two-way mirror; you can see them, but they can't see you - perhaps they only think they can but you know better... and in a way it's killing you inside to not be able to let your guard down.