She didn't even try to avoid their deaths

Even if she did, it didn't mean it won't happen in the future. Its butterfly effect.

That kind of things don't exist in reencarnation mangas they avoid anything bad that happens or try to avoid it normally if u know your parents are going to die in a unexpected accident since it's not unexpected anymore u try to do smth about it like "mom I'm lonely pls don't go" or some other excuse