In what circumstances will a judge strike down an argumentative and slanted instruction in a personal injury case?

To the extent that modification of appellants' proposed instruction based on evidence adduced at trial would have cured its argumentative and slanted nature, appellants' counsel was in the best position to make the necessary changes but did not do so. As we have previously observed, "It would not serve the impartial role of the trial judge to have made such major changes, particularly where the BAJI instructions adequately, if not ideally, stated [192 Cal.App.3d 699] 'the principles of law applicable to the key factual issue presented.' [Citation.]" (Wank v. Richman & Garrett, supra, 165 Cal.App.3d at p. 1114, 211 Cal.Rptr. 919.)