This is the worst game. Stealth is broken, weapons are useless. Climbing is the worst ingame mechanic I've ever played. Every mission is the same. Go from A to B. Zombies will see and hear you through all cover. They magically spawn on top, behind and even inside a locked room. Trash 10/100. Not worth the $3 I spent.
By far the worst section of this masterpiece of a game. After about 25 attempts at killing the shotgunner, I managed to sorint down the stairs and cheesed the section.
He doesn't explain well, but as soon as you grab the light motes go deposit them into the dark mote receptor in the cave, and when you grab the dark motes go deposit them into the receptor outside in the light. The opposites tripped me up, but we got there people!