...at a quick glance
Code:

action enemy_action {
	
	wait(1);
	c_updatehull(me, 0);
	// or
	// c_setminmax(me);
	// or set bbox flag in WED
	
//...
	//my.skill21 = c_trace(my.x,vector(0,0,-4000),use_box|ignore_me|ignore_passents|ignore_passable);
	vec_set(temp, my.x);  temp.z -= 1000; 
	my.skill21 = c_trace(my.x, temp, use_box | ignore_me | ignore_passents | ignore_passable); 
//...