The paramedic missions can be tricky, because you are not allowed to leave the vehicle without aborting. If you accidentally flip or destroy the ambulance, it's over. So you gotta drive extreme careful.
Every levels number matches the number of people that needs to be saved. The tricky part is, you can only transport 3 people at once and will have to drop them off at the hospital, before you can pick up more. So I would recommend always pick up the person first of who you assume to be the farthest away and pick up two more on your way back to the hospital. This should always gain you a comfort time cushion.
To save some extra seconds with every patient: As soon as the boarding animation of a passenger starts, you can start to accelerate again.
Note: If you drive a car and enter the health code (
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) the damage of your vehicle will be reset; the visible damage still remains however.
And, as always: Before you downvote this solution, please write down a comment first and tell me what might be the problem. Random, uncommented downvotes are just unfair to authors of solutuions. Thanks.