Spike is admittedly side-eying her a bit for the whole 'we'll do it together'. But he's not protesting. Carefully, and obviously, moving to be at her side too. Alert for any skittishness as he followed her lead.

It was probably a good thing she hadn't been able to see the visions. Or hear them. who knows what Buffy would've said to him or about him. And as much as he hated seeing the little bit like that, at least he wasn't watching her die. The aftermath had been bad enough.