They interviewed and used outside interviews of the people affected by the disaster. They also used other articles, research, and media to support the story and their beliefs.
The article addresses the lack of unity in the decision making proceess during emergencies. Lots of life-or-death decisions are left up to a doctor's judgemnet, which causes ambiguity as a result. One can argue that doctors are given this right to judgment as a sign of their training and the trust we put in them. However, when the trust is perceived as betrayed by affected individuals, the judgement is called into question.
Another point is the lack of evacuation preparadness in hospitals.
The article explains how a team of medical staff treated (and consequently killed) a number of patients following the flooding of a hospital in New Orleans. The staff in question overdosed the patients to put them out of their pain as they saved other patients who were more likely to survive. The article calls into question the process of triage and how we go about it. Who has the authority to make these decisions, and what lines do we draw between ethics and compassion. The article provides a play-by-play of the events leading up to the flooding, and relevant policies that existed and have been created related to this incident.