What is the proper rebuttal to a prosecutor's argument that a defendant's past record of good behavior might not hold true if he was sentenced to life without parole?

The prosecutor's argument properly focused on defendant's character and record. (See People v. Daniels, supra, 52 Cal.3d at p. 878, 277 Cal.Rptr. 122, 802 P.2d 906.) The prosecutor argued that defendant's past record of good behavior might not hold true if he were sentenced to life without parole, not that the prison system would be incapable of restraining or controlling any violence by defendant. The proper rebuttal to this argument was other evidence and argument directed to defendant's character and record, not evidence concerning the conditions of confinement if he were sentenced to life without parole.