User blog comment:Zolnir/RWBY Episode 8/General Reviews & Speculations/@comment-4365658-20130907052845/@comment-11188061-20130907075250

Wrong. She had that scar before fighting the Armored Golem. There's been many speculations on this but this part is definitely confirmed, because there were clearly screen shots that showed the blood trail to be different and not from the scar.

And Ruby just charged head on into an Armored Scorpion. She was clearly too young to be as matured as she was during the trailer.