A plothole discovered? Just an interesting insight I had after finishing the movie.

I have a big question regarding the police officer's death which I find could potentially be the biggest plot hole for the story. When the police officer was killed, wouldn't his colleague who were in the same police station report the case of a missing officer due to not being present for a certain amount of time? Especially knowing that the police officer escorted the Female lead's mother. After the report has happened, the police forces would have to start investigating deeper into the matter.

This would certainly lead to the outcome of having the police forces search the entire house because I don't think there is any amount of hiding that could work for the police to not notice something suspicious is going on in that house. By that point, with the number of blood shed, no amount of cleaning can rid the evidence (also, the police car and how sloppy she is to keep the carnage at a minimal) and there is too much circumstantial evidence leading to that house. They would investigate deep into who the last person being in contact with that police officer (which is the mom) thus they would try to search for the mom. Us knowing that the mom is murdered in that house as well, the family (FL and her dad) would be the next on the list to find. This lead to another chain of disappearance being discovered so a serial disappearance would be announced in the making. The psycho can't forever keep her own mother's disappearance a secret either as they are actively looking into the house, wanting to interrogate the mother too.

The police forces no matter how dumb they could be, would immediately know the common point of the family are that they have visited the same house with the FL mother who were once the "survivor" which has even pointed out her missing daughter and reported the issue to the police station and the fact that there is a police officer having escorted the lady.  

Why I would concentrate on this police officer is because I am implying that the psycho's future self would still be caught to the point where having access to the cordless phone is little. The only possibility that could have worked in the psycho's favor is either the time available before the police forces discover the missing police officer is super long to the point where she could remove every single evidence (though unlikely from what I said above) or if she ran away from the house as a fugitive with the phone in hand, the police would put a bounty on her right as they discover her crime so her life would be all about evading pursuit (perhaps until the police gave up on chasing her entirely). You may say that she could avoid the pursuit of the police force with the information presented by her future self but this is likely to be wrong as well.

Based on what I see of the rules presented, whenever the past is changed, the Female Leads has her circumstances changed but her location remains the same (such as driving a car with her dad but all of a sudden having the car/dad disappeared and being stuck in the same tunnel location). The psycho's future self who were once life imprisoned should nonetheless be stuck in the same cell because only the past self is the "true timeline". The evidence being burned by psycho's past selves is only happening in a much recent time so there should not be enough time for the psycho future self to actually get out of that prison and I am sure the prison is built in the same location. Explaining about the numerous refrigerators in that house would mean that she has spent a long time there to afford that many.

The ending definitely doesn't make sense as the Past self Female Lead were bound by ropes but Future self Female lead were freed up and is moving in the future timeline until the past psycho's self became awoken (where the future self female lead became bound as a reflection of her past due to the psycho killing her mom). In this case, it doesn't add up because we observed the rules where her future self was free to move at every point in time even when she was first initially bounded up. Maybe there was a number of possibility she could still be saved which was why she was still free to move around in her future timeline and only when it is a dead-end does she end up teleport all the way to the house basements. That could be the answer but I believe the question with the police officer still stands. There were enough circumstantial evidence to warrant suspicion on the psycho so a search warrant would be secured and she can't fake her mother's disappearance either. Thus, future self would still reach her own dead-end of being in a prison in all timeline. It should have been impossible for the future psycho self to be aware of her past memories since FL wasn't gaining any new memory from the "past timeline right as they happened).

Anyway, this movie is really thought provoking and me trying to start this discussion is not to hate on this movie but rather to show appreciation at the fact that it got me thinking this much and writing such a long discussion post that. The acting was phenomenal where I love the psycho's character design. The cinematography was indeed smooth and enjoyable along with the colors they used. The house went through so much with the transformation that I find it to be unique in terms of set design. The tension built  was exciting and largely the plot got me engaging. Just that I can't help but notice this large plothole  which should still make the "happy ending" a true one but without the presence of the mom. Only left with FL herself as the sole survivor when psycho bound her in that basement but was soon discovered by the police as the psycho gets captured and didn't kill her due to the psycho's own need to want to torture FL.

I try to treat the "psycho winning ending" as if it is fan-service as it doesn't fully make sense and I am guessing it is the director/writers motive to make it different from the usual happy ending (though it isn't execute well in my opinion). An ending I would think be more applicable is the capture of the psycho where she follows the original timeline of still being in life imprisoned because the number of killings have already reached a large amount with plenty of evidence and sus pointing straight at her. But because the psycho did woke up, the mother died as a consequence and FL would lose everything other than the memories which left her scarred forever (including the burned marks as a  reminder that changing the future causes a butterfly effect of immense proportion)  The scene where she dreamt of the nightmares affecting the past haunts her again.

p.s: What if she had always been bounded up in that basement since the start of the movie and that all of this happenings are lies she told herself? Like the psycho has said, she was a pathological liar who decide to wipe out her memory regarding the turning on the gas stove ever since she was young which causes her dad to die. So if that was traumatizing enough for her to create her own false memories of what went down, the day her mother die would be traumatizing similarly and she is now creating her own false memory as to what happen regarding all the fantasy time travelling portion. She is lying to herself that she stands a chance but in the end, she still fails and realized nothing has changed. She is still held hostage and never to leave this place.  Then it would have been the question of how she knows all the modern tech whilst trapped.