Sometimes the scorpion went far away behind the wall and could not get killed.
I played two times. And both of them are stuck because I cannot kill the run away scorpions. They hide far behind the wall. Even after I activate the X-ray, I could not see them. I could only see the aiming box but the laser's trajectory isn't targeting at the point I am aiming at. It seems like it will go upward after a certain distance. So, it's really hard to kill those run away scorpions.
I am not sure if they were trapped or not but they just didn't come out of their corner even if I went back to the other end of the room.