Badi Bee I know was foolish enough to reveal her plans of exposing Razia but what surprised me the most was Razia confessing her crime to Badi Bee. If we know Razia she is too cunning to even admit her good deeds, if at all any, forget about crimes!
But it was the CV's way of telling us the audience about Zoya's parentage, the history - the raaz - the secret that we are hearing for god knows how many months now. Through Razia's confession we know for sure Zoya is Mamu's daughter and her mom was killed by Razia which we expected from the day the factory incident was shown.
They can't make Razia confess to herself like she did last time in the factory, they had to do something different and so this declaration in a 'shahi' manner to Badi Bee of her crime. And this wouldn't have happened if Badi Bee didn't instigate her in the first place. So maybe this was Badi Bee's action is justified but nevertheless I don't think it was a good idea to openly announce how Razia will be exposed.
Moreover the evidence of the doll was burnt, so they need a live proof in form of Badi Bee to expose Razia. I sincerely hope that Badi Bee is smart enough to have some kind of proof here instead of just saying 'Razia told me...'!
Its kind of cinematic liberty the CV's took to inform us about Razia's plans, deeds and the past that will lead to the present and future.