Surely Nobuo realized in the end...

If he didn't get it by the time the news crew on the chopper died, the military guys in the hazmat suits dropped dead or hauled ass from him, and the three branches of the military tried to annihilate him, I don't think he ever will.

You're giving him too much credit. I guess you don't need brains to work as a lab assistant there. Also his grandpa(? *I forget*) asks what he did wrong now, after seeing him on tv. Makes you wonder what else he had been up to in the past.