The idea it's great, as well the atmosphere. The acting was also amazing. However there's so many little stupid mistakes.

1. Like when she was screaming to call him (to save the other girl), how did no one heard her? There were so many houses near by.
2. The last fight in the alley, how did no one saw it?? There were so many noise and so many people!!!
3. The police officer didn't deserve that happy ending, sorry, I get it that you are worried about your sister, but you didn't need him to find her, the deaf girl knew where she was, you could just search that area, since this is all in one night, the killer couldn't move. (and it was also inhuman). Also why didn't he ask for backup?
4. The mother could have done better in the police station, like push the suitcase to make noise and show the tools (but well she was too shocked to do something, what is understandable) , but how tf there's no cameras there?? And the police just saw a fight and let everyone go home??? bruh
5. And yeah lets let two people (covered in blood) running by the road.

But I'm not going to say, that I hated it. I love this fast thrillers movies. So I enjoy it for it.