If you mean confronting her in the piano room? It's not avoidable nor does it impact the ending. The only times there is optional chatter with her is after getting the key to the southwest section of the house and after surviving Mika the first time. Anything more than that is optional dialogue with her. Avoiding it and making sure to resist being prey whenever possible should trigger the Rebirth Ending.
I mean talking to her for anything other than story progression. Once you have the key you never need to speak to her again outside of interactions where the characters automatically speak, until you need to ask her to play the piano for you. You should tell her you would run when she asks what you would do in the worst case scenario. That alone should be more than enough.