When Ren rescues Hannah, gets her medicine, finds her a friend, and reunites her parents, Lev will call her and say the battery exploded. This locks her in to the "Ren didn't make it and she's with the Skeleton Who Can See Through Time" ending. The battery will cease to exist (retroactively, if necessary) if she re-awakens the Hus Old Gods. The implications are interesting as other comments from the Skeleton imply that she'd like to see Ren at the end. There's also something cyclic in that the Skeleton's name is Ki and that's the name Ren chooses for her daughter if she decides to have one in other endings.
Is that the canon ending? What does that mean? Maybe we'll find out in the future. I wrote this a month ago and forgot to post it, @#%$.