What points do the authors make about "Medical Murder" in Chapter Eight of The Will to Kill: Making Sense of Senseless Murder?

In Chapter Eight, entitled "Medical Murder," Fox, Levin, and Quinet address a particularly disturbing kind of homicide, namely the murder of people in hospitals and nursing homes. Describing these crimes as "serial in nature," the authors further categorize them as murders committed in order to "satisfy a variety of personal desires and psychological needs" on the part of the killers. In order to fit the category, these murders also have to be carried out in the "perpetrator's health care role." According to the authors, this grisly phenomenon arose more or less at the same time as the hospital itself became a professionalized institution, and is not all that uncommon--one man in the 1890s may have killed as many as 200 people, and a nurse named Charles Cullen received multiple life sentences for murdering over 35 patients at a number of institutions.
What causes these people to commit these heinous crimes? The authors point to a number of factors. First, the victims are uniquely vulnerable. Many are sick and helpless, and of course health care professionals have access to drugs and other things that can be used to kill people. Many medical murders, it seems, are driven by profit, but the main motive is the importance that the killers feel by having life-and-death control over patients. These "power killers" usually kill far more people, because, in short, they do not want to get caught. They are subtle and quiet. "Hero killers," on the other hand, "create a life and death emergency with the goal of...thrusting themselves into the center of the dramatic crisis." The chapter also describes "Munchausen Syndrome by Proxy," which is where people fake illness in another person in order to attract attention and create drama. Obviously, professionals are uniquely placed to be able to act on these desires. 
One reason, the authors argue, that these crimes are so common is that they are hard to prove--many people die, of course, in hospitals and nursing homes in particular, and many administrators may not be willing to admit that their staff is complicit in their deaths, even if accidentally. The authors conclude by looking at several ways to prevent these crimes. One is by tracking data on healthcare providers to look at the number of people that died under their care. Another is by providing support for remedying the stressful conditions in healthcare facilities that can cause staff to "snap." Finally, actually charging the accused with homicide, rather than negligence, which seems to happen in a shockingly large proportion of cases, might serve as a deterrent. 
Source: James Alan Fox, Jack Levin, and Kenna Quinet, The Will to Kill: Making Sense of Senseless Murder, 3rd ed. (New York: Pearson Education, 2008), 143-160.