Season 3, Episode 2: "Kill Ari Part 2"
As more information about Haswari began to surface, Ziva found herself conflicted. Would she help the man she thought she knew, or would she do what was right in order to help save Gibbs and the NCIS team?
In a harrowing scene, Ziva decided to put her past behind her and stand up for what was right. Instead of letting Haswari kill Gibbs, Ziva fired a single shot into Haswari's head, killing him and the threat he posed to the NCIS team.
Turned out Ziva wasn't such a bad girl after all.