So I don't know exactly how Toronto operates their ambulance service, but unless the family gave some bad details, the calltaker should have gleaned that they were likely dealing with a case of cardiac-related chest pain, and that's right at the top of the list of severe emergencies, regardless of how far along it has progressed, at least over here anyways.

I should add I feel a little queasy about dissecting this blog post for details. It seems more like a cathartic exercise for the author rather than some breakdown review of how the incident went, so it seems like some details were left out on purpose.

you dissected the blog post to ascertain how bad you thought traffic would be at that hour. that's actually what made me notice the timeline she had established and the appearance that it seemed to get more severe later.