@feha - That explanation makes sense too.
I was thinking that it was do to it being a rushed prototype built in only 4 days. She probably couldn't get efficient servos to handle the weight of collapsible forward armor, and there may be issues with its heat exhaust. There's no way you could fight efficiently and focus on the battle if your clothing was cooking you alive due to heat buildup. Who knows, maybe the heat is creating a barrier in front that can protect her too somehow.