This episode combines two noctorious murderers who were both known as the Angel of Death. Harold Shipman an English practitioner and American doctor Richard Angelo. If you weren't scared of staying overnight in the hospital now you will be.

Sources

Richard Angelo Sites

https://ivypanda.com/essays/richard-angelo-a-serial-killer-and-his-ethical-dilemma/

https://www.thoughtco.com/profile-of-serial-killer-richard-angelo-973130

https://en.wikipedia.org/wiki/Richard_Angelo

https://criminalminds.fandom.com/wiki/Richard_Angelo

Harold Shipman Sites

https://www.biography.com/crime-figure/harold-shipman

https://en.wikipedia.org/wiki/Harold_Shipman