To reference a particular spot or scene in a film or video etc. you just need to add a timestamp to the in text citation. You will find more information about this on the APA blog.
Example:
(OCD-UK, 2009, 4:03)
Example:
OCD-UK. (2009, February 26). A guide to cognitive behavioural therapy (CBT) [Video file]. Retrieved
from http://www.youtube.com/watch?v=ds3wHkwiuCo