Interesting. A case very similar to this is in the book "Emergency Response and Emergency Management Law" by William C. Nicholson. The name of the case is "American National Bank & Trust Company vs. City of Chicago". Essentially, a woman was in an apartment that the paramedics had access to, but never tried to the door or to locate the patient, except to knock on the suspected apartment.

I agree that if 3 ambulances failed to do something, it is systemic. Will wait for more details, and the probably law suit.