This is a bit dumb. There wasn't anything to set this up beforehand, it's completely out of nowhere and the tonal shift is really weird. Also the dad would have a million different ways to produce "a natural meeting" with Satoko and the police chief. "My sick daughter got lost!" "Someone tried to kill her!" Why would he, a supposedly doting and possessive father, put her in a situation, where she could have been sexually assaulted (and almost was!!!), when it would not only harm her, but destroy her marriage prospects. This feels like the author wanted to say "Aha, you all predicted the ending, because it was well planned out and made thematic sense, but I care more about surprising you, so here, look at this twist villain!!" What are you, modern Disney????