A fireman’s job is to save the houses and the lives of people from people. They need to be there as fast as they can so they can save the houses from fire. That is the reason why there are fire trucks. And these trucks must be fast to get to the destination or it will be too late.
In this game, you need to go as fast as you can to your destination so you can save lives. Though there isn’t any timer on the game, it is understood that you need to drive as fast as you can or it will be too late.