Because it took that long to get to the field, see what was going on, and start CPR, and then get the ambulance out there.
Professional trainers are as well trained as most paramedics—at least when it comes to CPR. I am sure there was a doc in that scrum as well.
Sometimes shit just happens.
The ambulance is always located adjacent to the field. The thing is brain damage can start at 3-4 minutes. According to the reports CPR was performed for 9 minutes before the defibrillator was used. An AED is pretty small. In an emergency someone can run from the ambulance to the patient.