PRIVATE.
Bruce Banner did an experiment years ago that turns him into a giant, green rage monster. He's learned to control it since, but at the time, stress of any kind would do change him. Him and Stark created an AI that decided to destroy the world. Bruce wanted to run away, but I couldn't. Not while there was still fighting so I pushed him over the ledge of a city that was flying up. Guess he didn't forgive me for that.