What if a juror dies or becomes ill at the time of the trial?

"If at any time, whether before or after the final submission of the case to the jury, a juror dies or becomes ill, or upon other good cause shown to the court is found to be unable to perform his or her duty, or if a juror requests a discharge and good cause appears therefor, the court may order the juror to be discharged and draw the name of an alternate, who shall then take a place in the jury box, and be subject to the same rules and regulations as though the alternate juror had been selected as one of the original jurors." (Pen. Code, 1089.) "A juror who is actually biased is unable to perform the duty to fairly deliberate and thus is subject to discharge. [Citations.]" (People v. Barnwell (2007) 41 Cal.4th 1038, 1051.)