Which has what to do with what?
The crazy ways people try to dispute or prove things with huge numbers of assumptions... lol.
Presuming you're trying to argue that you can tell from a chest wound(s), that Brown had his hands up makes the ridiculous assumption that when he was shot in the chest his hands were up instead of at some other time in the process.
Imagine the following scenario - for which there is no proof and yet it is as valid as any other - Brown starts running away, shots are fired and he turns around with his hands up - as he is turning around with his hands up, he is shot in the side. This makes Brown lower his arms and grab his side. He is now facing the officer and a round now enters his chest. Brown doubles over in pain towards the officer. The officer now puts one in the back/top of Brown's skull (because he's bent over enough for this to happen), Brown raises his head and catches the next one in the forehead.
Totally plausible - but more importantly - we have no f***ing idea if this actually happened or not.