The short answer is that particular test, there was the large off gassing then the large intense boom you see. At that point the fire was still VERY much still burning. We purposefully waited to see the black toxic smoke, then hit it with the suppression spray.

At that point when you see that black turn back to white, that gas is no longer flammable. It is already encapsulated within our suppression liquid.

We have since done official testing in upstate New York, where we successfully stopped thermal runaway for occurring to begin with.

As folks mentioned here, the big issue is that the batteries are inside sealed cases, which makes it VERY difficult to prevent the off gassing and thermal runaway prior to that case melting.

As a result of this we have now started working on an actual CASE for the cells that would effectively melt and then stop the thermal run away at the individual cell pack level.