She handed the phone back.
"Don't post it," she said.
"I wasn't going to," he said quickly. "I just felt like someone should have it. That it should exist somewhere. That it happened, and someone should have seen it and not looked away."
She looked at him for a moment. He was earnest in the specific, undefended way of someone who had not yet learned to wear armor over it. Genuinely earnest. The kind you did not see often in people his age, because most of them had discovered by now that sincerity without irony was a vulnerability.
"What's your name?" she asked.
"Seth. Seth Drummond. Second-year engineering."
"Why didn't you say something?" she asked. "In the cafeteria."
He looked at the table between them, then back at her.
"I've been thinking about that since it happened," he said. "I keep telling myself I was scared, but I'm not sure that is exactly right. I think I was waiting. Like I thought someone else was going to step in, and I could follow their lead. And then nobody did. And then it was over, and there was nothing to follow."
He held her gaze. "I'm sorry."
Ren considered him for a moment.
"What you did has a name," she said. "It is a well-documented psychological phenomenon. When more than one person witnesses something that requires a response, the likelihood of any single person responding goes down with every additional witness. Because everyone assumes that someone else will handle it. The responsibility gets distributed until nobody feels like they are personally the one who needs to act."
"That doesn't make it okay," Seth said.
"No," she agreed. "It doesn't. But understanding why we do something is the beginning of deciding whether we will do it the same way again."
He looked at her carefully. "How are you so calm about all of this?"
She was quiet for a moment. Outside the library window, the campus had gone dark, and the lamp posts had come on, casting small orange circles on the paths below.
"I'm not as calm as I look," she said.
It was a small thing to say. Simple. But something in the way she said it made Seth understand that it was also true, in a way she did not often allow herself to be out loud.
"What are you going to do?" he asked.
She pulled her textbook back toward her.
"Tonight, I am going to finish this chapter," she said. "And then I am going to think carefully about what I know and what I still need to find out. And then I am going to sleep."