We all have that inside voice that occasionally comes out and says things that others shouldn't hear. With your write, you described those walls falling down, No barriers left. Quite the scary thought. Well done with this.

Was it intentional for the form to be in the shape of a pawn?

It's scary to imagine if all our innermost thoughts escaped for all to see. You've expressed a 'mental crack' perfectly here. Well done :-) x
=^.^=

The title here made me think of a mental patient for some reason, one of which isn't actually 'mental' but who has had loads go on at one time and just cracked therefore been put into a mental asylum for their own good for a little while but they are on the mend now, they know they've been wronged and know why they've been put where they are but just want to go home now and plan their escape because their doctors don't feel they're ready just yet... I'm going on I know.
The first stanza confirms a little of what I thought of the title but then I thought of a mental block as in not being able to write a piece of poetry for some time because you've felt numb of any feeling and feeling is what kind of helps you write though I may be looking too much into it.
The second stanza seems to say that you speak your mind because you've lost all control of your feelings therefore you just tell people how you feel and you couldn't care less how you make them feel because you've been there, done that and got the t-shirt so to speak so why should you care?? But then again maybe it could be that you say nothing and they think they know you - like how you think, how you feel etc etc I hate how people think they know you, it really grinds my gears... Anyhowwww.
The last stanza again says to me you have no control over your feelings maybe through depression because of the cracks forming and I ask are the cracks forming because of the things people have said and done well the answer probably is yes which we shouldn't allow people to control us that way but it's extremely difficult not to isn't it?
This is an all round great piece.
X

I love and hate this. Because it hit it right on the head, how I myself feel most of the time. I'm always glancing around making sure no one is listening to my effed up head. Or stealing my secrets, fears, and insecurities.