AKA "HelicopterLoadingSus" (that's the actual name, I'm not joking) is a reversed version of the normal helicopter loading screen that only occurs when you complete the first half of the "Horizon HQ" mission.
As you'd expect, the audio and the colors in the video are reversed.
It also is... scary to hear. Doesn't feel right, you know... feels like something bad is bound to happen.
Asset taken from Trepang2's core file directory. I will delete this video at the request of Trepang Studios.