It was one of the most important times Naruto did something altruistic for the sake of someone else. The scene is also a great juxtaposition with Sakura’s and Sasuke’s final scene in Part 1.

Naruto's focus shifted to Sasuke, neglecting side characters ... the Mangekyou Sharingan, and its final form, the Eternal Mangekyo Sharingan. All three are accompanied by a host of other powerful ...

Naruto trained under ... Orochimaru became Sasuke's teacher because he gave him the Curse mark, and Tsunade was made Sakura's teacher as they were the final two members remaining from both factions.