Because Gabe was hardly advertising it. He didn't even want to talk about it. He just wanted to fix it. It was fucking unnatural, made his skin crawl and his ribs ache just thinking about it, and he wanted to fix it now.
"Now there's an invitation," he noted, but even his suggestive tone was worn thin, and barely half his attention was on it anyway. He reached up to the topmost shelf - a stretch even for him, and therefore completely out of the way of the curious seventh-years he'd been using as assistants for the past three days, since his magic started seriously dropping out. He'd had four different ones working on different parts of it, and at least one Hufflepuff in there who would hopefully be immune to the Slytherins and Ravenclaw suggesting that the whole project was a really interesting intellectual puzzle to put together.
Because the base of this - a slim vial of pale blue liquid, stoppered with glass - was not something Gabe wanted impressionable minds recreating. Speaking of which: "You've had the Curse before," Gabe said, watching William's face closely. "You're sure." The slightest hint that William was... he didn't know what. Lying in the name of science. Mistaken. Whatever. He wasn't going to be responsible for putting someone through that. Especially not William.