OK, so I get that it lights up the general direction of the enemy. First the red arch at a longer distance, then a slice at a shorter distance, and then a blinking red circle when right on top of you. I've noticed it's silence briefly before engagements catching me by surprise and while being stealthy (crouching and not moving) a moving target would approach my cavern and immediately stop like he knew I was there. What's the point in crouching? Does it have any effect. Does not moving have an effect. I understand the indicators, I need to understand what triggers it.