Simply forgot to reset variabel_1?
Not responsible for flaws / errors in code.
Code is "sample" only.
Code:
VECTOR* pl_vDest = { x=0; y=0; z=0; } // player dest VECTOR
var pl_bDest = 0;  // player dest VECTOR set (boolean)?
action player_mouseAct(){
	c_setminmax(me);
	VECTOR temp; vec_zero(temp);
	while(1){
		if(mouse_left==1){
			pl_bDest = 1;		// dest set
			vec_set(pl_vDest, mouse_pos3d.x);
		}
		if (pl_bDest) {
			vec_diff(temp, pl_vDest, my.x);
			vec_to_angle(temp, temp);
			temp.pan = ang(temp.pan - my.pan);
			temp.pan = min(abs(temp.pan), 5 * time_step) * sign(temp.pan);
			temp.tilt = 0;
			temp.roll = 0;
			c_rotate(me, temp, IGNORE_PASSABLE);
			if(vec_dist(my.x, pl_vDest) > (my.max_x * 1.75)) {
				c_move(me,vector(10*time_step,0,0),nullvector,IGNORE_ME|GLIDE|IGNORE_PASSABLE);
			}
		}
		wait(1);
	}
}