I was doing an f1 today and we discovered that there is a text screen bug. in the middle of the text screen there is a little square, you can't shoot through it. (I don't know if this is really a problem but you can just camp behind it and wait for someone to come in or just walk forward, shoot him and fast walk backwards)
Click here for the text screen bug
EDIT: You can only throw knifes through it, its bullet proof.