Ok, I need specific action declarations from everybody. You guys have basically one round before something happens. Kay'nar is airborne and out of line of fire, as described. Everybody else is basically on the trail, in the line of the rockslide, assuming it breaks through the damaged Wall of Stone. Getting off the trail will put you immediately in rough terrain that costs double movement (unless you can make a DC20 balance check to skip along the tops of the tumbled rocks).
The fathachs are at the top of a 20-foot rise, approximately 15 feet to the left of the trail. There is a hairpin turn and steep rise in the trail on the far side of the wall leading back up to where the fathachs are.
To answer Fenris' question: None of the big guys looks especially like a caster, and you're pretty sure the guy with the big axe is in charge.
The fathachs are at the top of a 20-foot rise, approximately 15 feet to the left of the trail. There is a hairpin turn and steep rise in the trail on the far side of the wall leading back up to where the fathachs are.
To answer Fenris' question: None of the big guys looks especially like a caster, and you're pretty sure the guy with the big axe is in charge.