Those are not Zebra Stripes. The Zebra Pattern is activated when you turn on the "Over Exposure Warning" in the settings and is only a guide to show you which parts of the image are being over-exposed, and as such would appear in the highlights not the shadows. It's never recorded onto the video file itself.
That being said, I have seen some horrible footage from the Inspire1 (which uses the same camera under the hood), but have never seen that kinda artefacts.
I agree with your mate that you should not shoot in Auto mode. Have you seen this on other videos or just this one?