My uncle died of AIDS several years ago. He was a physician, as was his partner, and we're pretty sure that a group of their friends had a pact to help anyone in the group die should they begin to suffer hugely. He had almost no symptoms for years and suddenly, everything descended on him. His partner called my mom and said, "Your brother died a few hours ago and he was cremated a couple of hours later so you guys don't really have to come if you're busy."
I forgot what hints we got over the years but the death pact theory really began to make sense after awhile. Part of me gets why they did it and part of me is horrified by the idea of putting a lucid human to death. I really, really have mixed feelings.