He didn't know she'd do that, why would she? No one sane should want to give up the Alpha spark. But then his family was hardly sane were they?
"I didn't...I wasn't myself." If he'd been himself he would have taken on Satomi or someone else. Peter really did try to keep his family from getting hurt. It just never worked out that way.
"There's no scent...you're not really here are you?" Now that he was realizing she didn't have a scent he realized she didn't look exactly right either. So she really was dead and gone.