>> reporter: he certainly is. i think it's very clear that he has been ground down and exhausted by this relentless pursuit by gerrie nel. he's been on the stand for over a week now. the majority of that time has been having to endure searing cross-examination and off and on on a pa dan tick and detailed basis. that the judge will be looking out to see what she feels is natural tripping up because of tirededness or confusion, versus tripping up as a sign of a mistruth or fabrication and, therefore, draw negative inference in terms of his testimony. simply because he trips up, it doesn't necessarily mean that will have a damning impact on his case. but he run the risk of the judge drawing that inference. >> all right, kelly phillip from outside the courthouse in pretoria. we will of course go live to the