was talking about the second person, and that only one person had blue eyes. the second person would think the same about the first person. when they see how neither of them leaves the island on the first day, they’d both realize they also have blue eyes, so they’d both have to leave on the second day.
the same thing would happen if there are three (a), (b), and (c). this is because the first person would see how the other two don’t leave the island, so this person must have blue eyes too. that would mean all three would have to leave the third day, after first seeing that the 