Amazing!
However, for regular folks, rapid cooling is the numero uno thing to remember for anything associated with burns. That can't be repeated too many times.
Rapid cooling can be the difference between needing that sort of treatment and more superficial burns. Believe me, "superficial" burns are plenty painful enough.
As for exactly how long you should cool it, exactly how cold you should cool it (ice-cold or slightly below luke warm?), applying burns gel etc - those details are secondary to starting cooling as fast as possible with whatever method accessible there and then. SPEED IS IMPORTANT. Only when you've started the cooling process you can beging thinking about and fiddling around with improving the method. Such as replacing ice-cold water with slightly less cold water etc. etc.
Of course, having a good plan to start with is a great investment.