Vanko didn't die. Hammer staged his death and recruited him. Hammer picked up the government contract that you had given up and hired him to make suits similar to yours, and at the expo he revealed them, not knowing that Vanko had connected Rhodes' suit to his system. At the expo, Vanko activated the suits and they caused chaos, hurting and nearly killing hundreds of people. I went to Hammer's HQ and hacked his system and restored control to Rhodes so that you and he could defeat Vanko.