The character played by Michael Cerveris in this episode, Dr. William Halsted, is based on the real-life physician William Stewart Halsted (September 23, 1852-September 7, 1922). Halstead, who the showrunners have credited as the major inspiration for the character of Dr. John Thackery, was both an innovative and pioneering surgeon and a drug addict (as Thackery does, he attempted to cure his cocaine addition by becoming addicted to opiates/heroin instead).