This low budget film (7 grands only) by Shane Carruth is the most realistic of time machine flics
and there are many like (back to the future, the time machine, looper, assassin creed,
interstellar, terminator etc).
There are more twists in modern time. Where does a phone call go if multiple copies
of a person are around. What happens if a copy starts to duplicate itself in a
fail safe machine. Despite all the precautions, multiple copies of Aaron circulate.
Can future Aaron go back and undo all? One can see that Carruth has a degree in math and
also was a software engineer.