This Portal falling video is how I think time works: only things that allow for themselves in the future are created in the past. When I got off the edge of the portal and stopped falling, it’s like if someone went back in time and tried to kill their grandfather: it just wouldn’t work. You immediately are prevented.
I think time is like when things drop from one portal on a ceiling to another on the floor: only things that make it through both happen.
The only things that can be experienced in time are things that don’t cause themselves to not exist in the past.
When you move and stop falling through the portals, you stop yourself from having the experience in the first place. That is, only if somehow you never get back to the portal to fall through again and fix the timeline.
This is why the time travel Grandfather Paradox, where you go back in time and kill your grandfather and so are never born, cannot happen. You can only do actions that do not prevent you from traveling back in time and doing the actions. This idea is called the restricted action resolution theory.
If you try to shoot your grandfather, you will only be able to do if you are still able to “portal” through time and shoot.
Just some thoughts!