"Speak Up, Please"

Charge: murder of V. Dr. Jones is called to the stand by the prosecution. At D's request the judge first listens to Dr. Jones's testimony out of the presence of the jury. Jones states that just before V died, Jones said to her, "You are very badly wounded," and that shortly thereafter V mumbled, "D did it." The judge thinks that V probably knew she was dying but recognized that reasonable people might differ on that question. The judge also thinks that V probably did not say, "D did it," but rather mumbled something else which the doctor misunderstood, but the judge recognizes that reasonable persons might also differ on that. Defense counsel objects to Jones's being allowed to testify before the jury. What ruling and why?