Not going to work as a blackmail video if you are in it committing a crime.The point is (I agree it's really stupid), he drugs her and films it, so that he can later blackmail her with the video, so that she'll bang him not drugged. So uh...blackmail...I guess?
You can't say "do what I say otherwise I'll post this video of me committing statutory rape"
Dark path makes the most sense in this scenario.