She didn't slam the door. She simply said: "Your heart has no tolerance class, Marco. It’s either perfect fit or rejection."
Since this is a highly technical phrase, I assume you’d like a that incorporates this concept metaphorically or literally. Here’s one: Title: The Tolerance of Falling tolleranza iso 2768
He wrote a letter to Elena: "I have been living by iso 2768. But you taught me the most important tolerance — accepting what doesn't fit the drawing. Come back. I'll leave room for the irregular." She didn't slam the door
Marco had spent twenty years designing precision gears for racing engines. Every night he came home, washed the coolant smell from his hands, and measured his life against the ISO 2768 standard hanging on his workshop wall: General tolerances for linear and angular dimensions. Here’s one: Title: The Tolerance of Falling He