According to Comic Book Movie on March 2, some film footage of Joss Whedon's "Avengers: Age of Ultron" film had been taken through what appears to be a window of an upstairs office. The sound of someone yelling "action" launches actors posing as bystanders and local authorities react to what looks to be an explosion in the middle of the street.
This particular cut scene being filmed could represent an impact being made by an opposing force that may be later edited in for the purpose of special effects. One could imagine the Hulk making landfall or maybe even the villain Ultron, but fans can only speculate one of many things that simulated impact may be.
That being said, since "Avengers 2" is currently underway, according to writer Drew Pearce, had mentioned that Whedon is ready to direct "Avengers 3". Pearce was also asked about the new Marvel One-Shot film short, "All Hail the King" and its repercussions in the Marvel Cinematic Universe. Pearce was rather cryptic in his response.
"One of the things when you're a writer or director in the Marvel universe is you come in, you leave some tasty morsels dangling at the end, and maybe you're the one who comes in and picks them up again next time, or maybe it's someone else, or maybe they just hang there awhile and that's fine too". That's all you can really hope to do. Unless you're Joss [Whedon] and you're making 'Avengers 2' and '3,' and then you have a pretty good idea if you're making the next one or not".
Though Pearce did backtrack some on his Twitter feed later saying he really has no idea about Whedon's involvement in "Avengers 3".
(Though, duh, I have NO IDEA whether Joss is actually coming back for Avengers 3)".
So Marvel fan conspiracy theorists may think there's an attempt to cover up information in some form.
"Avengers: Age of Ultron" is scheduled to be released on May 1, 2015.