Just a Bit of Story . . .

The stillness in the room was made all the more overwhelming by the interruption of Sam irregularly gasping for breath. Severus had gone too far, and he knew it. But he had to know why she refused to protect herself from the abuse. And now, he had his answer.
He moved towards Sam and grabbed her by the shoulders too hard. He saw the fear in her eyes but couldn’t be concerned with it now. This was too important.
He spoke slowly, emphasizing each word. “Never — say — that — again.”
She avoided looking at him.
“Do you understand me, Samantha Snape? Never!”
She didn’t move, staring at the ground, seeming to study his shoes. “Yes {sir}.”
“No, Sam. Listen to me: you never once deserved it.”
She looked up at him, a strange look on her tear-stained face.

[That's the first time he calls her Sam instead of Samantha.]