I have watched for that error everywhere, since.

The quiet colleague, the deferential relative, the person who never makes trouble — we assume, from their peacefulness, that they are not capable of ferocity, and we are so often wrong, because peacefulness is usually not incapacity but choice, and the gentlest people frequently have the most formidable strength held quietly in reserve, waiting for a reason.

My father found my grandmother’s reason.

He did not survive the discovery of what she actually was.