First of all: don't fucking imply I don't have empathy because I don't understand people wanting to redeem a character designed to not want redemption. That's taking a video game and a discussion about its characters too far, and is quite frankly insulting. Seriously, fuck off with that shit.
Second of all Vaylin is a cruel sadist to you even before you taunt her, and I think you are to begin with vastly overselling how much you taunt her if you don't want to taunt her. You aren't triggering her to be evil, she's a sadistic murderer even before you talk to her. Every line she has for you is how much fun it'll be to kill you and all your friends.