*spoiler* a flaw i noted.

Imagine, you are in a dark room, got a night vision handycam in your hand, you can see everything,everyone, but no one can see you 'cause there is no light in the room, as in the last killing of the movie.

But think about it , your lcd (screen) is emitting light, so other person can also tell your situation, he can't see you but can definitely tell that, you are there and exactly how far from him.

In [REC], as far as i remember the person had a camera which didn't had screen, maybe i am wrong, then that movie also has this flaw.