Gabriel's too interested to notice how Rhys is emotionally backing away from the subject. His answer is practically a 'yes', and it makes Gabriel feel less alone.

"I killed someone, too," he replies. "But he wasn't doing anything to me. He came to me for help, and I just- it was like it didn't matter, what I was doing. Not until afterwards."

He's not worried about sharing, because he figures that's why he's here. It has to be, right? He belongs here.