[Zankoku12]

^

Spoiler:

From what I can made out about the treasure,obviously Saya wanted the time machine but she knew that impossible so she asked that masked man to make it some sort of nuclear weapon instead as a way to end her story.

Well,Rin nad Riki got each other and the bond with their friends while Saya/Aya got no one.And if we look at her situation again : A little girl being half buried alive under a huge landslide in a middle of nowhere and it's raining. She even described how her body start getting so cold and she couldn't move or feel her left arm.
And where could that miracle coming from if the dude she loves can't even remember her (he's too busy going to the beach to have fun with his friends anyway). Not to mention if she really went back in time then that mean she would just repeat her death and died all over again
So anyway,that's why I prefer if the ending's flashback is actually Aya's own dream world.

Also because I like crushing people's hope and dream ~