Here Peugeot announces a fire-fighting CAR called the "H20". It is all-electric, running on hydrogen fuel cells. The hydrogen is made by the car. That means it needs oxygen too, so it either gets it from the air or uses a spare tank if the air conditions are too smoky. I gather that's the point of the vehicle.
Its auxiliary power unit can run pumps and communications gear.
I'm not sure I get why you'd permanently mount a teeny ladder to the roof. If you want to have something permanently attached, you could make it taller because the car would provide the ballast.
But this is a concept car and there will be some time to work out the bugs if it goes into production.