It was the last time he heard the name his parents had given him when his mother gave birth to him - Ben. Ben, his weak and foolish former self, which he thought he had destroyed forever. Moments before, his father stood before him, and now he was no longer there. He was no longer there because he had murdered him.

Kylo Ren could still feel his father’s hand caressing his cheek as Han Solo's dead body fell into the abyss.
And now it was back, his former self Ben. Suddenly he felt sorrow for what he had done instead of relief from his inner pain. Tears welled up in his eyes, tears of regret.
Supreme Leader Snoke had warned him not to give in to his feelings. They had once been his grandfather's undoing. Kylo did not want to make the same mistake. But the small part of Ben that had survived inside him remembered the rare times together with his father aboard the Millennium Falcon. They were full of joy and adventure.

Ever since he had betrayed his uncle and the New Jedi Order, he had been torn, torn between the light side and the dark side of the Force. He had thought killing his own father was the test he had to face that Snoke had mentioned. But the pain was still there and he still felt torn.