It appears people are more afraid of a mass killer than a serial killer who will rack up a bigger score over a longer period of time.
Go figure.
Most people can't visualize themselves ever becoming the victim of a serial killer. Serial killers tend to target people on the fringes of society; prostitutes, drug users, homeless people. The Ted Bundys out there snatching up college students are extremely rare.
Mass shootings, on the other hand, can happen anywhere and anyone can be a victim.