The phrasing on that was strange, and it caught Ford's ear. My potion. One of his own invention? That didn't bode well for Ford's chances of being able to figure this all out after the fact from describing it to Noble, but he wasn't giving up on that possibility just yet. Darrow was... not a reliable narrator at the moment, Ford suspected. He couldn't imagine that Darrow was always this way, because he didn't know how Noble and he could have been friends if he was, but at the moment he was certainly a little less than sane.

"You don't know what you're doing at all," Ford pushed. Darrow had hinted at that, with what he'd said next: he didn't realize he would need it again so soon. Ford was speculating a bit, but he thought he was working from some degree of truth as he continued: "You're messing around, and you got in way over your head."

Hopefully that hit home — it would frustrated Darrow more if it was just a verbalization of something that he'd already been thinking. And frustrating Darrow was currently Ford's only viable strategy when it came to distracting him from making this mystery potion.