Bruce nodded, watching her actions and he deft fingers, which made him shiver. He breathed, low and slow, and smiled, letting himself calm. Calm, he must be. Damnit.
At her words, he nodded, stepping away, then back to her, thinking, then nodding and looking to her. "Radiation can effect the human genome, both long term causing normal mutation, and short term, causing a faster mutation. A sudden one. I was... exposed to high levels of gamma radiation, enough to..." He paused, then started again. "Enough to power this whole city for 100 years, including this lab, without strain or tapping the reserves."
Old memories surfaced and his look was both sorrow, horror, and old pain. "It changed me, releasing, if you will, my inner Hyde, and giving him a form all his own. A ten foot tall, over muscled, green form, one filled with superhuman strength and toughness, like a troll of old myths, or a giant of old stories. And as this... Hulk, I vented all the inner rage within me."
Again, his voice dropped as he fell back into science talk. "Now, when the body or the mind are exposed to the growing exponential of stress, of any kind, but especially anger, it triggers the genetic switch, and I change into the Hulk, a being who expresses the inner rage, pain, and less friendly aspects of my own personality, as a fresh and independent mentality." And he fell silent, looking her in the eyes with eyes that burned with intensity, and were touched with green.