The duo came out of the villa to go and pick up Zane from the school. Anya had two choices, one to take a legal route or confront Gianna.
The retribution from the legal route would be simply exhausting and time-consuming. Anya didn't have so much patience to see Gianna suffer.
The bitterness from Flora's attack hadn't subsided despite knowing Flora was going to end up in prison. To make Gianna's life a living hell, to make her pay for everything she had done for Alvin, Zane, and Anya, Gianna should live, repenting for her actions for the rest of her life.
Anya could only do that by snatching away what Gianna loved the most.
Anya hated that she was having such vile thoughts but she couldn't bring herself to just sit and endure, especially when Gianna was a poisonous snake that would find ways to trouble them.
Anya looked at Alvin, she could actually ask him to deal with Gianna but how is it any less vicious than doing it on her own?
