Yes they do set fire to the pan.
Not everytime but quite often.
They heat the oil and add a little very finely chopped onion/pepper or garlic/ginger puree
This is cooked for about three minutes and the oil gets very hot because there is very little in the pan.
It's at this point they add a spoon of the curry gravy.
This splutters like mad and a sheet of flame goes up
Watch out if you try this, it is potentially very dangerous
Keep a damp teatowel nearby to smother the flame and watch out for your hair too!
They add more curry gravy, bit by bit, with diminishing burning results.
The other time they do a flame thing, is while the pan is simmering.
Their gas rings are larger than on a domestic cooker.
The flames creep up the side of the pan and the little splutters it makes keep producing little flames.
About the size of a match flame.
If your curries are lacking a little "depth" try this......it makes a big difference.
Make your curry gravy as usual.
Heat about three tablespoons of veg oil
Very finely chop 2 fat cloves of garlic. Get the bits really small
Fry them until brown (carefull not to burn)
Stir the oil and garlic into your curry gravy
Use the next day
This really gives a massive amount of extra flavour, and one that you should recognise