I was thinking that since Cynthia's usually around Veronica and Astrid, both of who are unkillable, that would make her invincible as well, but you're right. Since few know of Astrid, the lion share of the blame will go towards her which puts her in a lot of danger.
I think Kane's reaction will likely depend on his alignment. Good Kane will probably be temporarily mad but ultimately forgiving of and embracing her, while Evil Kane will either disown her or pretend to forgive her and try to use her.
Another random thought
If Kane goes down the kill-all Karlsson path, does Nadia follow him down that path, or will she heed Calista's words and either refute Kane or try to convince him of another way?