The movie jfk does not make sense?

ok my mom is watching this movie which in my opinion sucks ***, but anyway...the jury is asked to leave i dont understand why, the one guy said that he has used an alliace one second the next he said no...no only this but this stupid freaking magic bullet or what ever theory didnt make sense cuz he said oh it did this and did this oh and then a bullet that was clean was put here, his argument before was that there was three shots what he was saying that happened couldnt have happened with 3 bullets