It's not like you're a foreigner with 〜じゃあるまいし

Shin’ichi’s teenage friend Ran enters Professor Agasa’s house looking for Shin’ichi, unaware that he was forced to take a poison that inadvertently turned the teenager into a young child. When Ran sees the boy and asks his name, Shin’ichi recalls Agasa’s suggesting that he not reveal who he is. Panicking, he gives the name “Conan”, explaining the oddness of it by saying his father is a fan of author Arthur Conan Doyle.