IIRC, that "250K people killed by medical error" includes every time a medical caregiver failed to prevent an already sick or injured individual from dying and didn't follow ideal procedures in retrospect. One of the examples was "the doctor didn't tell a patient with heart disease that jogging would be dangerous, and then the guy had a heart attack while jogging".

That's like saying that "hospitals cause most cancer deaths" because people who have cancer are in the care of professionals before they expire.

People who die from guns aren't being euthanized from already impending death.