>ruins what could be the best arc in the series and possible the series itself

why she did it?

Is Petra unable to do the shit she vowed not to do, or is she supposed to spend the rest of her life consciously trying her best to comply with her vows?
What happens if someone holds Petra's hand without her consent? Does that count as "grasp someone's hand"? What if someone tickles Petra? Does it count as "showing weakness in front of others" if she reacts in any way?
Depending on the consequences from breaking a vow, Petra may be a safety hazard to be around

Insane older Petra is a real possibility now
Tappei, I kneel