Oh, you could introduce some Umbridge-like character in the Wizengamot who had a grandchild kidnapped and they didn't find him/her in time and now the character is really pissed off or just feels hurt and vindictive and forces the Head Auror's hand. And you're right. Canonically, Aurors cannot be bad. But you could make her single and a career woman so she of course wouldn't understand family matters and would think that work is first.