It was too good a moment to spoil by bringing up anything related to the Joker. No doubt the mere name would send her spiraling into depression, what to speak of revealing how Eddie had struck a bargain with Joker - he would cause a spectacular distraction in exchange for Harley. So, let Harley believe whatever she wanted - Eddie would not tell. Seeing her safe and away from the abusive hands of the Joker was its own reward.
And yet... his compulsive nature tickled at his consciousness with a need to show how clever he'd been, and so he recited, "It can be cracked, it can be made, it can be told, it can be played. From it, you're sold, and this plot paid."
Before Harley could linger too long on the answer to his riddle, Eddie wagged a finger at the screens. "Back to work, you! You've got to focus on your responsibility! How can you ever be a criminal mastermind like me if you don't focus?!" He paused to stare at one of the screens, noticing something very interesting. "Pull up camera number 12." When Harley did, they could clearly see one of the masked vigilantes on the scene, fighting with a gang of prisoners. Picking up the microphone, he narrated for the viewing audience to hear, "It looks like the party's really begun with the arrival of our first guest! And yet, no Batman? He has only seven minutes before the next hostage is executed!"