It's very important for fire engines to get to their destinations as fast as possible, but it's equally, if not more, important for them to be able to, you know, put out the fire using water. That's where this MiG-engine-equipped fire engine goes wrong.
Sure, slapping a jet engine on a fire truck is insane and will give it unparalleled speed, but when you need to remove the water tanks to make room for the engine, it seems to me that you're doing more harm than good. Not to mention the issues with maneuverability that you'd have trying to steer a truck with a MiG engine on the back. Overall, I give it an A for effort and a D- for thinking things through before starting a project.