Only once did Antonin ever step over the invisible line he set for himself. They had just come home from a dangerous and violent raid. Hermione saw no reason to move out of his house. A couple of Death Eaters had been lost, several enemies had been killed. Each of them had been in grave danger. He quite literally saved her life. At home, free from prying eyes, he berated her for her carelessness. Unwilling to stand there without defending her actions, she shouted back. He pressed her against a wall and kissed her. As the heated kiss escalated, he grew bold enough to touch her wherever he wished. She was certain she would've gone to bed with him, but at a critical moment, they were both summoned to the Dark Lord. He'd been embarrassed that he'd allowed his emotions to control his actions. When he didn't try again immediately, she moved on and went off with another.