Just chucking my thoughts into the mix here...

I find the idea of integration much less frightening when I think of it simply as the dissolution of dissociation. Not a single thing is lost other than the dissociative barriers between all the parts. No-one gets killed off (it's impossible). No-one leaves (also impossible). Its just that the barriers between everyone come down and you are all there together, experiencing all the things together.
That's what I imagine and hope for, anyway!