That was the issue, really. Terrence knew quite a bit about the potion - too much, really, considering he wished the thing didn't exist - but could say very little. He felt a surge of hatred again for the potion that had kept him complacent for years, that had stressed his relationship with Ella more than should have been possible, that had nearly ruined his friendship with Katie, and made other friendships - ones with people he now knew were under the influence - difficult for him to handle.
But the information was out, now. He had seen to that, by helping Weasley and Granger break into Crouch's office and find the information that he hadn't been able to give them. They'd even found more than he knew about, such as the creator of the potion. He didn't feel that information weighing on him as much anymore, now that the secret was out. After the meeting, Kingsley ought to know as much about it as he did.
"Well," he said, frowning, "The Mark on my arm might come in useful for that, I suppose." He could stand to herd people around for important things, as he'd done when he'd needed to find out immediately whether Ella or Alek were in the hospital. For their own sake, he could order people around. He'd run the risk of being perceived as part of a threat, but that might actually be useful to him in certain situations, if he was trying to keep his cover around the Death Eaters. And he should be able to handle the risk of becoming a target for someone pretending to be under the potion who didn't like being ordered around by him. Especially since he'd probably be able to tell whether they were pretending, now. Still, he had the mental image of showing his Mark to a whole mob of pretenders in an attempt to corral them into a safehouse, and ending up getting stampeded. It made him laugh, but then he sobered again. "I'd rather controlling them were a back-up plan, though. Better if we could get the information out there and let people decide for themselves."
That also involved getting certain people who wouldn't be on their side out from under the potion, but those people were already risks. And knowing that they'd been controlled by a potion could turn a lot of people against the government who would otherwise be neutral, which was the case with Terrence himself.
He gave Kingsley a level look at his last statement, at the hard look in his eyes. He hadn't suspected the man of being a part of that, but it was good to hear, all the same. He simply gave a nod, and was silent for a moment, expression unreadable when their drinks were delivered. He grabbed a packet of sugar and emptied it into his coffee, stirring thoughtfully. "Work on getting the Prophet staff off it first, maybe," he said. "See if they can't get something into the paper, get the word out there."