Well, clearly Atom isn't a stranger to responsibility. Rezo's eyebrows lift in a brief, minute expression of surprise before he begins properly pondering what Atom told him.

"Have you ever wanted to harm anyone?" he asks after a few moments. "You say that robots like yourself were mistreated by humans. Did that ever make you angry?"

It's perhaps a question he asks more out of curiosity than anything else, but it does tie into Atom's concerns about if he'll be able to fight at all.