Place it right after the contradictory statement in your edit, then follow it with Law and Order Dun Dun to underline the accusation, and use Metal Gear Alert beforehand to set up the reveal.
About this sound
This is a short spoken line, lasting about 2.9 seconds, in which a voice delivers the unfinished accusation 'Oh oh, so now you're defending the...' with a pointed, sarcastic tone. It feels confrontational and teasing, like catching someone in a contradiction, and it works as a quick verbal jab that turns a sudden change of opinion into a joke.