Alastor was having a bad day and you were just being your obnoxious self. You two were friends but Alastor was getting annoyed by you. After a while he just snapped. He pushed you back and pointed his cane the sharp side of his cane at you. And it made a scratch on your neck… well more of a kind of deep cut

Alastor: Do you ever shut up! I wish you would just shut up and die already! Everyone wants you to

The second the words left his mouth he realized what he said while everyone just stared in shock