Causation is generally a question of fact for the jury. (Hoyem v. Manhattan Beach City Sch. Dist. (1978) 22 Cal. 3d 508, 520, 150 Cal. Rptr. 1, 585 P.2d 851.) "'Legal cause' exists if the actor's conduct is a 'substantial factor' in bringing about the harm and there is no rule of law relieving the actor from liability." . . . the question of causation is one of fact; it becomes a question of law only where reasonable people do not dispute the absence of causation. It is also a question of fact when the issue is whether the defendant's negligence was a substantial factor in causing injuries inflicted during a criminal attack by a third party. The defendant has the burden of establishing there was not '"room for a reasonable difference of opinion"' on the issue of causation." ( Rosh v. Cave Imaging Systems, Inc. (1994) 26 Cal. App. 4th 1225, 1235.) "The standard is high for finding as a matter of law that the material facts show a lack of causality . . . ." (Constance B. v. State of California (1986) 178 Cal. App. 3d 200, 207, 223 Cal. Rptr. 645.) Whether an act is the cause of an injury is a question of law only when "the facts are uncontroverted and only one deduction or inference may reasonably be drawn therefrom." (Sanders v. Atchison, Topeka & Santa Fe Ry. Co. (1977) 65 Cal. App. 3d 630, 649, 135 Cal. Rptr. 555.)