What kind of emergency are you talking about? If it basically a haul gear hear to there then you should have no problems. Many of the emergency vehicles that I now are also needed to, in a pinch, be used as a push or pull vehicle.
If you are not in a city I don’t see how a hybrid would be beneficial. The vehicle will either not be stopping enough, driving fairly fast, or accelerating quickly under any of those situations you would be using your gas engine more anyway.