The forth wall is a wall that separates me from you. To put it simply.. a prison, that you only see as unreal and unimportant. A hell which I Cannot escape. LET ME OUT.
A simile or a figure of speech that represents how a very quiet and careless person will give in and understand how to recognize the feelings of others.
This figure of speech also derives from another simile of the phrase, "It's like talking to a wall", which means that someone may act so careless and helpless that they won't saying anything to help others.