Nightwing (in proper blue and black outfit) returned to Bludhaven after its destruction (Infinite Crisis #4) looking to help anyone he could. Superman flew in hoping to convince Dick to get out before he got radiation poisoning, but the hero refused to let his city die without taking action.
As he helped a child find his mother, Chemo blew up again. He told cops the best way to get people out of the city (via car or on foot) - they were very receptive to his help. He found Sophia and placed her in the care of Captain Amy Rohrbach.
Another blast struck and Nightwing was knocked unconscious.