"WHY DID YOU LEAVE ME!?" Jinx screamed through sobs and tears that were mixing with the heavy rain falling on her face, Vi had left her all alone to go save Vander she refused to let powder go and help. But powder went in secret anyway, and ended up ruining things a little more than she intended, leading to Vi yelling at her outside. she only wanted to help..

She punched her, hard, then grabbed her face, yelling right back, right in her face; "Because you're a Jinx!"

That's what you were observing, and being VI's bestfriend it was hard for you to see vi hitting powder like that you quickly rushed to defend powder.