This is just my interpretation of whole scene.
I think the vagueness of Kozue's words -- "you mean that?" makes it a bit confusing. I guess in the context we're supposed to imply it to mean "oh? the train~?" "is Kozue going somewhere (away)?" like producer asked what she was up to or something off page.
Then producer proclaiming or reassuring that he'll follow Kozue no matter where she goes (career or otherwise) as a supporter. All tying into the idea that she isn't alone anymore. gist of pgs 26-28
Still confusing regardless.
The first panel is in reference to the previous page, not the page it's on.
I think Kozue didn't understand why Producer took her to see everyone, because she isn't afraid of being alone. Despite not being afraid of being alone, she's nervous and unsure of herself here. After Producer asks her if she had a good time, he doesn't say much for a second and Kozue just talks, where Kozue speaks more directly than usual and says that while it's okay to be alone, it makes her chest feel all fluttery. We get a very pretty half page visual of her having this realization, then in the next page we get a cute lower detail drawing as she realizes this is why Producer was worried about her feeling alone.
It's strange that that one panel is disconnected from the conversation on the rest of the page, but the rest of the page and the next page are also a somewhat confusing conversation about Kozue's growth as an idol. They're just going to the lesson with Mio you see in a few pages, so Kozue is not being literal here from the very beginning of the conversation.
I thought about changing it to "that's what you mean?" or "that's what you were referring to?" but those both felt too stiff, and neither fixes the problem with it being unclear which page that panel is referring to.
The flow of time in this chapter is actually pretty loose. There are several flashbacks to events that occured at another time that aren't explicitly made obvious. The bottom half of page 17, and the spreads on page 22 and 23 are both in the past, because the character outfits change.