When the second Age of Ultron trailer came out, some people noticed how the Hulk’s eyes were red and much more savage-like during the Hulkbuster fight. With some new toy reveals, we know what may have brought out the “Savage” Hulk in the movie.
Now, it’s never a good idea to try to predict plot points from LEGO sets. I explained why right here. But when a set corresponds to something we’ve already seen in a trailer…it’s possible there’s something there.
New descriptions of the Age of Ultron LEGO sets are out, and from the Hulkbuster one comes this:
Hulk has been trapped by the powers of Scarlet Witch and she is ready to fire an electrical bolt if he tries to escape! Place Iron Man in the cockpit of the humungous Hulk Buster suit and rush to the rescue. On the way you must fend off aerial attacks from the flying Ultron.
While Ultron isn’t in that scene in the trailer, Scarlet Witch messing with Banner’s mind is a very good explanation as to why he’s going berserk and fighting Iron Man.