2513
Finally , he said , in February 1996 , ` ` three registered nurses came forward to report a patient ' s , a health care professional ' s , a hospital ' s worst nightmare : There was a killer amongst them . ' '
 a hospital, he, three registered nurses, a patient, a health care professional, a killer, them
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: geographical social political, organization, person, location, facility, vehicle, weapon 
Text: {0} 
Answer:
 a hospital, he, three registered nurses, a patient, a health care professional, a killer, them