Fast Enough - S1-E23
Question: At the end of this episode when Eddie Thawne shoots himself to stop Eobard Thawne from being born, wouldn't that mean Barry Allen's mom would have never been stabbed? So essentially The Flash could've saved his mom from being stabbed anyway.
Answer: The show explains in another episode that The Speed Force leaves copies of characters that no longer exist in the past to avoid paradoxes such as this example.
Question: Why didn't Darth Vader kill Ahsoka?
Chosen answer: No one can explain how time travel works. If by committing suicide Barry's mom survived, then there would be no Flash nor Eobard Thawne. So Eddie wouldn't commit suicide in the first place, because nothing would have happened.