Dum Dum Dugan says exactly what he needs to say to convince Maria Hill to take her international police force and attack an American city with troops and nuclear weapons in order to destroy the Extremis installation. She fires on Stark's command, who was trying to race the event horizon of the device (which swallows the nuclear fallout in a black hole that evaporates into Hawking radiation) before his armour failed. Scans show no signs of life within the event horizon.
