No comment on the de-aging and gender swapping, Katie? Warren smiled inwardly. He didn't know if she had realized it, but if he had doubts about his suspicion, or wishful thinking that this might actually be a new girl at the Institute he'd never met before, they were gone now when she completely avoided that topic. Sure, a new girl could have already heard, already talked about it, and already knew all there was to know. But would a new girl show up in the halls wearing mens sneakers and undershirt? Given the current state of confusion at the school, probably not.
Considering that this person had already lied to him, in that case, giving him a false name (not that he'd asked, but it had been socially appropriate to provide one when Warren gave his), Warren saw it as game on. He could play and see how far whoever this was would take it. Somewhere along the way, he'd find out who it was, too.
"The Bronx, interesting borough. I used to fight crime there when I was younger." he chuckled at the memory of Avenging Angel, moving Katie's hand to the crook of his arm to hold more securely against his side and patted her fingers. "What is your particular mutation, if I may ask?" He glanced down again at her, meeting her eyes a moment before looking ahead, still smiling pleasantly.