A Brilliant Thriller with an Unforeseen Twist

Rating: 9/10 (24 June 2016)

I would have rated it a perfect 10/10 if not because of this:
The movie ended with an inconclusive state for Ginny.
If we say she did not survive, we assume two scenarios: (1) Each key represents the personality that was killed off in Malcolm's psyche. So, all in all 10 personalities have died. (2) Ginny was the sixth one to be killed. This means that she has key #5 with her - remember that we are counting the killings in descending order.
HOWEVER..
It was shown nowhere in the movie how Ginny was killed by Timmy. So, it can be said that aside from Timmy (who was seen walking away from the car explosion), Ginny (whose body was never found after the explosion) also remained alive.
Although we can safely say that the reason why we never saw Ginny's body after the explosion was because it happened at the same time all the bodies started disappearing, it would have been better if they showed the scene where Timmy killed Ginny. Like, for example: As soon as Ginny and Timmy got inside the car, Timmy gets out while Ginny starts the engine. Timmy runs away from the car as far as he can (because he knows it's about to explode), and as Ginny steps out of the car to call Timmy, the car explodes.