It's flat as a tack north of airfield. The photo is deceptive due to the colour changes of the vegetation. The dark green is mangrove trees on the edge of a creek then there is the lighter green of the scrub.
At this stage, in the absence of any more definitive information, it looks awfully like somatogravic illusion has trapped this fellow. It always crossed my mind as a possibility every time I taxied out at Tennant Creek at night. I can also remember a discussion about it on PPRuNe years ago and the recommendation then was attitude flying but the suggestion was an initial 5 degrees then after gear retraction go to just under 10.
Personally, I always transition to instruments on takeoff at night and have used that initial 5 then 8 degree attitude.