Clearly you do not understand seppuku.
She has failed,
Therefore, to regain her honour, she commits seppuku.
If she hesitates, all honour is lost.
to make sure she pulls it off, she gets a friend to stand over her, with a sword raised, ready to cut her head off at the first sign of hesitation, therefore preserving honour.
This girl was a pussy, so her friend cut her head off to preserve her honour.