Why did Nick kill Dr Garner in Basic Instinct?

In "Basic Instinct," Nick Curran kills Dr. Beth Garner during a confrontation fueled by a mix of personal and professional conflicts. He discovers her manipulative nature and the truth behind the murders she is linked to, which culminates in a heated moment. Ultimately, the act is driven by a combination of self-defense and the overwhelming emotions tied to their complex relationship, making it a pivotal point in the film's psychological thriller narrative.