One of the more confusing sequences in Zack Snyder's Batman v Superman: Dawn of Justice is the "Knightmare Sequence". It's unclear what exactly is happening: is it a premonition? An alternate future? Can Bruce Wayne (Ben Affleck) see the future in his dreams? And then why did Flash (Ezra Miller) suddenly appear with a warning but was also "too soon"? What exactly is going on? Here's the video in case you need a brief refresher, although it leaves out the Flash part.
Since we all have an inordinate amount of free time right now, Snyder did a live commentary on the social media app Vero for the Ultimate Edition of Batman v Superman and explained what exactly was happening in this scene. Per THR:
Snyder said the sequence is a byproduct of the Flash (Ezra Miller) using the cosmic treadmill and creating a rift in time. There was going to be scene in a later film in which we would have seen Bruce Wayne and Cyborg deliberating on what point to send the Flash back to so that he can prevent Lois’ death. Snyder revealed that it is Lois Lane’s death that leaves Superman open to being infected by Darkseid’s Anti-Life Equation, and the incident that would have led to the Knightmare future the Justice League would have attempted to avoid.
It's kind of funny that even though we never got to Zack Snyder's climatic Justice League sequel, he and Marvel came to the same conclusion: using time travel to save the world.
On the one hand, I get what Snyder is trying to do here with his Knightmare sequence by teasing Justice League later, but there's also a lot of confusion. Again, the scene as it exists is unclear if it's actually happening or just Bruce's fear. It's clear that Snyder revels in his "grey areas" (in other points in his commentary, he talks about constantly trying to push Superman into that zone, although I'll counter that zone is weakened when you still don't have a good idea of Superman's character), but that level of ambiguity can sometimes lead to confusion. There's a lot here—cosmic treadmills, the Anti-Life Equation, Darkseid—that simply would not make sense unless you got to your planned sequel. Again, I understand where Snyder was coming from, but there may have been cleaner pathways to build towards Justice League than what he came up with.