"Uncomprehending Feelings" (分からない感情, Wakaranai Omoi) is chapter 288 of the original Naruto manga.
Although Yamato hopes he will be able to convince Sasori's spy that he is the real Sasori, it is likely his cover will be blown at some point and they will need to capture the spy. As such, they practice their teamwork in a combat scenario the next day. Sai does not hesitate to sacrifice Naruto in order to complete the exercise. Naruto once again compares him to Sasuke, saying that Sasuke would not betray a team-mate like that. Although Sai disagrees with this point, he only reminds Naruto that his absence of emotion makes it impossible for him to think of anything but the mission's success.