nor able to sweep up brick dust on the floor for decades because it is “destined” to be reverse-bullet damage that is fixed in the future.
(In the movie, you see them walk into a pre-damaged room that is later ‘repaired’ by the inverted gunfire that caused it)
Here is my explanation, first I will introduce a scene from the movie to help explain.
Before the second pass of the airport heist when the protagonist and Neil are in the shipping container the protagonist starts noticing a wound manifesting on his arm and then it starts to bleed. Later in the fight with himself from the first pass of the heist he is stabbed in the arm but since he is moving backwards in time him being stabbed heals the wound. From his perspective he is stabbed directly in the wound and then the blade is pulled out and he is healed.
What I want to highlight is when the wound starts manifesting itself in the shipping container. This is not the natural healing process happening in reverse as one might initially assume. I have 2 reasons for thinking this.
The wound manifests much faster than the body would take to heal. The bleeding starts happening way too soon before he is stabbed.
His entire body is moving backwards in time. The main character does not materialise a chocolate bar out of his mouth when trying to eat.
What this means is that the wound that is manifesting on his arm is being caused by some unexplained phenomenon as a result of reverse entropy objects interacting. Not by his body healing in reverse, not by him being stabbed (because the stab heals him)
To extrapolate this to the glass window that takes a reverse entropy bullet. Here is the order of events from the perspective of a standard entropy glass window.
The glass is manufactured and installed (no bullet hole in the glass)
A bullet hole is manifested in the glass by the reverse entropy phenomenon. This scatters the glass for later.
A reverse entropy bullet flies through the broken glass window and it is repaired.
This can be seen in the car chase scene as well. The mirror of the BMW is in perfect condition. During the chase but before it collides with anything the mirror starts getting more and more damaged until eventually being hit by a reverse entropy object and returning to perfect condition. I believe that in the logic of the movie when a standard entropy object interacts with a reverse entropy object some of the reverse entropy properties are passed on to the standard entropy object that makes it manifest the damage done to it, or alternatively makes it repair the damage done to it depending on your perspective.
I may not be explaining this as well as I would like to. Please ask questions about parts that don’t make sense. I love thinking about this sci-fi premise and I’m pretty confident I have a consistent (though perhaps not realistic) explanation.