"Angel of death" is a title given to more than one nurse.  In fact, it has been used to describe doctors as well as nurses and others that kill within the medical field.  Charlie Cullen definitely isn't alone in his killing.  You are supposed to feel safe and to be cared for in a hospital, but sometimes, anything but that takes place.  The stories of Orville Lynn Masters and Genene Jones, both killer nurses, are discussed in this episode of Petrafaction Horror Stories.  Real Monsters are the scariest stories of all!

References:

Angel Of Death’ May Have Given Lethal Injections To More Than 130 As A Nurse, July 7, 2019, 8:50 PM ET

Genene Jones Biography - Facts, Childhood, Family Life & Crimes, From thefamouspeople.com

Texas Nurse Dubbed 'Angel Of Death' For Baby Killings Has Last Conviction Upheld

August 26, 2021, 3:32 PM ET