There had to either be an antidote (with whoever made the original potion having made it or someone off the potion a while), or they could make one. They needed to either find it or make it - one of the two and without wasting any time. They had no time to spare, and each day mattered.
"I doubt drawing a mark would work," Kingsley thought out loud as he served, "It's probably tied into the magic." Was fear of the power of Death Eaters enough to persuade some people? Or perhaps the magic would work. It was a bit unsure. They would have to test it out before using it in a crisis situation.
If Death Eaters were to be trusted to be on their side, it was a pity there weren't more on their side. If more of them had authority, that would be useful. But the acts they committed...the public didn't know, but Kingsley did. And he didn't think he could do that. Working as a hit wizard was bad enough. "I don't think I could become one," he sighed, but it was better not to be like them - to be better than them. He pushed some food onto his fork and ate it, looking across at her.