We all know that ER is famous for its deaths. Not only of the patients that are served by Chicago's County General but of its staff as well. Particularly in its emergency room. Fact of the matter is, there have been so many deaths of ER personnel that I'm surprised that a police investigation hasn't been opened to determined if they were natural or a bit suspicious. Some of these deaths have been shocking, such as Lucy Knight's during season six. Others were long in coming, like Mark Greene's peaceful death in season 8.