What is the test for causation in a medical malpractice case?

Contrary to the majority's implication, were this case permitted to proceed it would not go to the jury on "`abstract negligence [alone]'" (maj. opn., ante, 107 Cal.Rptr.2d at p. 624, 23 P.3d at p. 1150), nor, emphatically, would allowing trial on causation "`make the landowner the insurer of the absolute safety of everyone who enters the premises'" (id. at p. 625, 23 P.3d at p. 1150). Plaintiffs causation evidence, including her own testimony and that of her expert, is both detailed and nonspeculative. And affirmance on plaintiffs causation theory would vindicate nothing more than the established principle that, "[w]here the occupier of land is aware of a concealed condition involving in the absence of precautions an unreasonable risk of harm to those coming in contact with it ..., the trier of fact can reasonably conclude that a failure to warn or to repair the condition constitutes negligence." (Rowland v. Christian (1968) 69 Cal.2d 108, 119, 70 Cal.Rptr. 97, 443 P.2d 561.)