Did Octavian tell Octavia that he and Pullo killed the Evander? I can't remember. Octavian, the master thinker he is, now knows Servilla used his sister for information to damn his family. Servilla is screwed, assuming they take a brief detour from history.
Yeah, he did tell Octavia that he tortured and killed a man. It is unclear if Octavian is aware that Servilla used this information to help the senators kill Julius Caesar.
I looked at the rage on Octavian's face and thought for sure he was going to kill the wench right there. But that would have been quite a turn from history.
"Octavian, the master thinker he is, now knows Servilla used his sister for information to damn his family."
...and we know how much Octavian loves his sister! (sorry, couldn't resist.)