The broker tries to find the cheapest air ambulance provider so they can make the most profit possible from the flight. The broker is a business person, not a medical provider. They don’t have the experience to understand the differences between air ambulance companies, and they don’t fully understand the medical needs of each specific patient.
Possible Safety issues:

1. The broker may not fully check out the air ambulance provider
2. Quality of patient care is an unknown quantity
3. Crews may or may not have proper training
4. Brokers deal with the most discounted air ambulance providers to enhance their own profitability, not patient care.