he's been on the stand all morning point by point taking every piece of the prosecutors case and e vviserating it. here was a moment that stood out because a big part of this case is george zimmerman said he was trying to pin trayvon martin's hand's done after sustaining a big old beating and why was he found face down w his hands under his body after a gunshot to the heart. dr. vincent had quite the explanation for this. look how he put it to this jury. >> even if i reached across and put my hand through your chest, grabbed your heartnd ripped it out you could talk to me for 10 to 15 seconds or walk over to me because the thing that's controlling your movement and ability to speak is the brain. that has a reserve supply of 10 to 15 seconds. now that's minimum. that assumes no blood is going to the brain. >> from what i understand you to say then for at least 10 to 15 seconds after mr. martin sustained the shot he could have been capable of talking and of voluntary movement? >> he could, right. some people just lose consciousness immediately. it's psychological. it's not physical. he has the p