Derek hunts down the kanima in this scene from the Teen Wolf episode "Frenemy."
Added:
Colton has a powerful reaction to Allison and Scott getting closer on Teen Wolf. "Frenemy" is the sixth episode of the show's second season.
Added:

Teen Wolf Season 2 Episode 6 Quotes

Guy: Does that mean maybe I could?
Lydia: If you want me to punch you in the throat.

Stiles: You couldn't catch his scent?
Scott: I don't think he has one.