I don't know... Naruto seems like he's in that "I'm gonna beat your arse" type mood.
I don't blame him, after everything they've been through for months now, Sasuke decided to pull out this crap now, I'd want to kill Sasuke too. But, tbh, I don't think Naruto will kill Sasuke. Probably just going to end up like the Final Valley fight again and the ending reversed where no one dies, but Sasuke is left there again. Idk if the LAST instance will be similar, but I'm getting that PTS vibe