Spoilers... Ending Complete Ruins the Films Logic

Rating: 6/10 (23 May 2019)

Spoilers Ahead, DO NOT CONTINUE!!
Look, it's an interesting film that's an ok way to kill 2 hours. But the ending complete ruins the entire premise of the film.
The mother we believe to be the good mother is actually the "evil" version (who swapped identities in the beginning of the film unbeknownst to the audience).
1. The original premise - that the mother does not remember what happened in the mirror house, is perfectly logical. She has amnesia due to fear. However, the amnesia and fear does not hold up if the mother was the evil version all along. There should be no amnesia and the only reason for it is to deliberately trick the audience.
2. If the mom was the evil version all along, she shouldn't be scared of a "shadow" of herself as she claims. Sure she could be scared (of being revealed to be a fraud by the true her) but not of a shadow. Again, purposeful misleading to set up the twist.
3. Why does the good version go insane and deciude the only way to get revenge on her evil self is to raise an army of evil duplicates that murder their good halves? Again, contrived and makes no sense.
4. Why didn't/ couldn't the good version of the girl use the escalators to escape the evil realm? This really doesn't make sense.
5. How the hell did all of the evil versions have enough food/ water to survive?
6. Surely not every single copy of everyone in the world was stored in the one bunker shown. So how did the "Good" girl convince all of the evil copies (of all the rest of the world) to arise??
There are probably many many MANY more issues with this film. But god does it destroy itself trying way too hard to set up a profound twist that is just completely illogical.