Lead by 1 or lead by 2, it really dosnt matter a fg takes the lead. He went for the conversion to lead by a fg that way all KC could do with a fg was tie.
It was too early to be worried about that. So say we don't get the 2, and we didn't. and late in the game we are down by 4 instead of 3, where a FG would tie it but you now need a touchdown.