After the Kiss-Off.
Oswald's plan had come off, had come together successfully, although not in the way he had expected.
They hadn't stuck to the script word-for-word. The scheme he had composed had been faultless to a tee, and although he and Jim had got lost so much in their own little world, the desired effect had been the same. And the effect of their desire had been to aim true and hit the bullseye.
At first, Oswald had wondered, if only briefly, if it would be a tad too cruel to kiss Barbara's-ex-fiancee-now-his-betrothed in front of her. It would be really be rubbing that perfect little nose of hers in it.
But then, he had recalled just how vicious had been her treatment of him, along with Tabitha and Nygma. Tabitha had almost throttled the life out of him with that evil whip, and she had taunted him mercilessly over his mother's murder, rubbing so much salt into his wound. And Barbara had just stood there and laughed about it!
Oswald had pretended to be forgiving towards Barbara for her part in it - to make her think he had let bygones be bygones - and now, this was the best way he could think of to hurt her mentally. He had more than an inkling that she still harbored affections for Jim, no matter how much she tried to protest to the contrary. He could read the love in her eyes for Jim, just as he could see in her eyes that she held him in contempt.
No, her facade didn't impress him or fool him one iota - not any more….
And he was glad to make her hate him even more for taking Jim away.
"Come, James," he had said, after they had kissed and he had delivered the coup de grace so gracefully. "Let's go somewhere a little more….upbeat. It feels like a morgue in here!"