Board Thread:Speculation House/@comment-16348034-20130823234203/@comment-17720343-20130827004406

If Yang doesn't know how to use it, then it stands to reason that she doesn't know how to activate it when in need, which she clearly does, as shown in her trailer when she brings her two fists together. Any kid can turn on a car, but good luck finding a kid that can drive.

Same principal. She can probably activate/deactivate it, but lacks the skill to control it when its active.