In truth, the private conversation Vaughn and Amelia had held in the office of the Head of the Department of Magical Law Enforcement had concerned more than just Azkaban.
Amelia had been deeply dissatisfied at the time, mainly over the Potions exchange, but she also knew that there had been no real political thaw between Vaughn and Fudge. Both sides were merely going through the motions.
After working with Vaughn several times, Amelia had come to understand him somewhat. She had always felt that, even as Fudge raked in political credit, a Sword of Damocles had already been quietly suspended above his head.
Vaughn held its hilt. So although Amelia was somewhat displeased with him and Dumbledore, she continued to work closely with them.
She simply had not expected Vaughn to act so soon, or so decisively.
When Amelia heard that Vaughn intended to make a major issue of Azkaban and listened to his entire plan, she actually thought he had gone mad.
Helping a prisoner escape-if that came to light, not only Vaughn but she herself would be finished!
Amelia was fundamentally different from Fudge. Although she had clear political ambitions, she was not purely a political creature, and the fairness and rigor most people saw in her were no act.
Amelia had her own principles, so her first instinct was to refuse.
But when Vaughn produced the photograph of a fat rat with a missing toe and revealed the truth of what had happened all those years ago, much of her resistance faded.
After Vaughn explained Azkaban's vulnerabilities and the uncontrollable nature of the Dementors, Amelia was completely persuaded. The benefits behind the scheme, in particular, were simply too tempting to refuse.
She also wanted to use this opportunity to work with Vaughn and eliminate the lurking danger