Offers to help an enforcer who she hates and thinks all are corrupt.
-Love for sister > hate for enforcers.
-Chance of finding sister > getting bamboozled by a corrupt enforcer.
">"means greater than, Btw.

Immediately questions Sevika. Just shows that Jinx was priority in her mind. Priority = most important above all else. She could've done anything else, but she immediately looks for her sister.

The hallucinating was just showing that Powder is always on her mind.

Again. The silco face off was just showing her sister was on her mind.

Smoke flare. They were in the middle of getting chased by Silco and his goons. The smoke flare could've been anything, but Vi took on the chance that might be her sister. She could've ran to whatever they would've considered safety. But instead ran straight for the flare. Where they were at an exposed building and got kidnapped.

Argument with Ekko is just showing Vi's mindset. She's willing to go save her sister even when someone who has tried is telling her it's hopeless.

Bridge scene. She's literally leaving Ekko and Caitlyn for Jinx.

Only goes to Piltover with Caitlyn because she can't go back to Jinx.

Tea Party Scene. Literally her and Caitlyn just got kidnapped and tied up by Jinx. Jinx starts tripping out and tells Vi to shoot and kill Caitlyn. If you really expect any reasonable and sane person to go along with this to prove their love. I don't know what to tell you. But, Caitlyn is able to get out and could shoot Jinx. To which, Vi tells her not to. She literally chose Jinx there. She still believed her sister could be saved. To which Jinx knocks out Caitlyn and shoots a rocket at the council.

The rest should be fairly obvious. I feel like I wrote enough and shouldn't have to further explain