Even if one sleeps, their brain catches on vibes and alerts them either by signalling them with a dream or just waking them up. Exactly what happened with Nivritti. Her brain wanted her to wake up and showed her Dae in her dream, no, a nightmare.
She could feel something was about to happen. She woke up with a jerk and looked all around. Everything was fine. Her mother was sleeping soundly next to her. All the doors and windows were locked. There was no way Dae would enter inside her house.
Idiot, Vicktor! Why did he have to warn her? Now her mind was making scenarios about how Dae could hurt her. She knew he couldn't walk to her house as he had no idea where she lived. He didn't even know that she knew Korean which meant that he didn't read her resume or ever checked her employee page.