When you are apt to get shot at...especially in today's threat environment you do what you have to do to avoid giving the enemy an easy shot at you.
Nothing unusual in the video.....increasing height a bit in order to dip your rotor blades into a turn....common practice when flying low in combat.
Laying the aircraft over on its side to pass between trees rather than popping up....is another maneuver that would have Nutty peeing his pants I bet.
Flying under power lines...bridges....down winding river beds....in ravines, canyons.....anything to hide is on the menu.
You trade risk for gain....as in all tactical situations.
This video was made to show off the BO-105 rather than demonstrate tactical flying but gives a good idea of what it like.
I never took a hit flying low and fast which is how we learned to do it in flight school but the Army in some very bad thinking moved away from that until the NVA showed up with MANPAD SAM's....then things changed.