She was allowed to be afraid, after everything that monster had taken from her and in many ways was still able to take from her even when he was locked away. And now he was free - escaped from Azkaban making the world just that much worse. It made her wonder how many others could have escaped. What other dangers were out there, waiting to attack.
"If he had do you think we would be even sitting here simply having this conversation?" And there it was, Lavender turning her fear or even sadness into anger. Anger was always easier to focus, it could give her some sort of strength when she had none and she was going to need it. "But does that mean you have reason to think he will? And that the Ministry actually has no idea where he is?" Because that just filled her with confidence.