Actors generally need their scene partners in order to perform well, and now it looks like their battle against the villain was filmed without actually having anyone to play to.
But Ciarán Hinds filming completely separate from the rest of the actors may be cause for alarm.
While Zack Snyder’s projects are typically extremely CGI heavy, at least the actors are together filming in their green screen set.
If the scene is all action like the fight against Doomsday then that’s one thing, but Steppenwolf will presumably have some dialogue as well.