You're right bud, in one respect. The bottom is cooked by the heat of the tawa, but without the heat on the other side, it's going to end up like a scone. In Chris's video the naan is only on the tawa for ten or fifteen seconds before turning over.
Having tried it, I think that the flame is not only to finish and colour the bread, but is crucial in the cooking process.
Good luck and have a Very Happy New Year