Try to imagine defense counsel's dilemma as a plaintiff's expert, answering jurors' questions, takes over the trial. The witness proceeds to expound, lecture and even stride the courtroom floor -- sometimes even straying from his area of expertise. Does the defense keep silent? Or object and thereby risk alienating the jurors? It's a quandary posed by the practice -- as seen in the latest New Jersey Vioxx trial -- of allowing juror questions, and there seem to be few guidelines to resolve it.