Hey man, don't worry about it, this is an international forum, English can be difficult. You seem kind of like a more junior/early in your career guy so, I'm happy to help out and explain.

Covered in this case means that they don't have to pay some third party to take that risk for them, they can just get the ambulance as part of the nominal fee everyone pays per year or whatever.

When you outline a problem statement, you want to map out what the person outlining the specs really mean. It takes practice.