"Ah, but here's the rub - no offense, Lisa, but I'm doing this for me, not you." He gestured to himself with his glass, resisting the urge to spill his wine everywhere. "You understand, don't you? You're stuck in the middle and I'm sorry for that, I really am," he nodded empathically, "But there's just nothing I can do about it! He irritated me, and I'm here to irritate him back."

Nobody tells the Joker he can't do something, or that something he'd do wouldn't matter. It all mattered.

"But at least you're being such a good sport about this. Playing along, letting me ask my little questions and always coming back to Jackson, did you notice that by the by? That I'm still asking about him, but you're more relaxed about it now because you know I'm only curious, I'm not really trying to get into your noggin." He laughed, "And I know if Jackie is anything like my dear doctor, he just loves getting into your space, making you have to answer the really tough questions. But no no no, I won't do that to you. Don't worry."

He could wait until a more opportune moment.