[TOMT][MOVIE][2000s] Thriller about people trapped in a room with killers among them

At first, I tried to write a description of the film myself, but because of my poor English grammar, it turned out to be an unintelligible mess. So I uploaded the description to the neural network, which also didn’t give me an answer, which I watched as a child, but structured my So I uploaded the description to the neural network, which also didn’t give me the answer that I watched as a child, but structured my description.
I would be very grateful if I wasn’t the only one who watched this movie.

Plot:
– A woman (possibly blonde(not sure at all!)) wakes up in a monotone, windowless room with bare walls, a toilet, and a locked exit door.
– There are about 12(more or less) other confused and scared people with her.
– A voice over a loudspeaker announces that among them are three killers (a rapist, a strangler, and a maniac). Their goal is to identify them.
– People start dying: lights go off, and someone is killed in the dark.
– At one point, a Black police officer is forced to make a choice—his daughter is threatened live, and he shoots himself in the head to save her, but not kill anybody.
– In the end, only the main heroine and a sympathetic man survive. He says, “Everything will be okay,” but she coldly stabs him with a shard of glass/metal, slits his stomach open, and kills him while staring into his eyes—revealing she was the “maniac” all along.
– Final scene: She walks out through a door, and the camera reveals a production crew monitoring everything (like a twisted reality show).

Additional details:
– Watched on a pirated DVD around 2009–2010 (film likely released before 2010, When I was about 10-11, but I’m not sure.).
– Low-budget, possibly indie or non-American (Spanish/French?). I watched it in Russian and it was a full dubbing.
That’s all I remember for sure, I watched this movie fifteen years ago, if not more, but I’ve been looking for it for ten years now.