Like most things, it gets pretty complicated. I went through 200 hours of training (EMT) which essentially helps me sort into what makes me go safe, go fast to a medic en route or a hospital, and go fast to a hospital (where a paramedic can't help much or at all). The goal of all Emergency medical personnel is to get people to definitive care (not EMS).

Asking a lay person to know what a BLS (non-EMT fire & police), EMT (Ambulance), Parmedic, or MSO can take care of, or even what the differences are, is, I don't think, super useful. The red vehicle shows up and takes you to care.

In the case of MCI, EMTs can a) give aspirin or nitro (rx), b) have an AED and lots of CPR training but have to stop the vehicle to give effective compressions, c) a radio and the ability to meet up with Paramedics.

Paramedics have more complex treatments (drugs) and EKGs, but it's still 2 folks in a truck, not a hospital. They can do amazing things.

But as the joke goes, sometimes the best treatment is High Volume Diesel Therapy (burn rubber).