In level 2, go to the green phonesin Zaibatsu Village and answer the bottom one. Do the job up to the part when you have to steal a fire truck. Take it back to the village. A man will get in and the weapon will change from the water cannon to a flamethrower. Whether you complete the job or not, the truck is yours unless it explodes. If you fail you can do it over to get another flamethrowing fire truck.