Only two things can cool a dude down when the temp hits the mid-90s and there’s no water in sight: adrenaline and wind chill. Cameron Zink and Kyle Strait find both in “The Descent: Part II,” an off-road BMX caper filmed in Utah and sponsored by G-Shock. The two riders own the high desert, wall riding eons of sedimentary rock and charging down terrain too steep to hike. But wait for the grand finale. Zink stomps a monster blind backflip that’s simply chilling.