Yup, Takami mentioned to Ozaki that he snuck in back during the "Ikumi talks too damn much" chapter. That's also when it mentioned the newly crafted lawn/garden (that withered away in the heat) that's mentioned here as the cause for concern, with the ground being recently uprooted.

On the audience side we get more details and are basically spoon-fed any medical school level knowledge needed to understand where Toshio's understanding is as a doctor. Imagine being Seishin who's watching all this, only has as much as Toshio bothers to explain to him, and who has no capacity to ponder it for himself medically and thus doesn't even know what he doesn't know, and has his asshole of a friend also undermining all of his suppositions on it apparently just for the sake of Devil's Advocating. "I think it's suspicious too and have compiled data and research on it. But I'm going to watch TV and pretend it's nothing until you 'convince' me of what I already think is the case."

It's like he got all the worst qualities of a doctor AND a lawyer put into one pointy-faced package.