Paramedics did not owe a duty of care to an adult car driver who, following a head-on collision, repeatedly told the paramedics she was not injured and did not want or need medical assistance–even after the paramedics warned her she should be seen at a hospital and might have sustained injuries that were still asymptomatic. After the paramedics left her alone, plaintiff suffered a stroke, triggered by the collision. To establish liability under the negligent undertaking doctrine, the plaintiff must allege not only a voluntary undertaking to provide aid but also show the defendant’s conduct increased the harm, or the risk of the harm, inflicted by the third party. Here, plaintiff did not allege those two prerequisites.