Place it right after the reveal in a short edit, then follow it with the Law and Order Dun Dun sting to underline the twist, or lead into it with the Metal Gear Alert cue when a character gets caught out.
關於此聲音
This short clip is a single spoken line, 'But I did not know that!', delivered in a startled, wide-eyed tone as if the speaker has just heard surprising news for the first time. It feels funny and awkward in the best way, turning a moment of being caught out into a light, self-aware admission that lands best when the surprise is genuine.