Just rewatched Age of Ultron after seeing Infinity War at the weekend, and realised that this scene is probably meant as a foreshadowing of the Avengers showdown with Thanos in Infinity War/Avengers 4.
UPDATE: 08/12/2018 - So the title of Avengers 4 dropped today and it looks like I was right that this is an intentional piece of foreshadowing back in 2015...
![](https://i.ytimg.com/vi/CU33HZQz0hI/maxresdefault.jpg)