There's always the hope that someone will try putting out a Caesium fire with water: although it might be less energetic than firefighters' foam spontaneously igniting on contact with fluorine.
The glaring omission is that they didn't try FOOF, the super-duper oxidant available to any cheerful and insouciant chemist who relishes the vigorous oxidation of Oxygen by Fluorine, and knows it's someone else's problem to store the stuff.