I have it all figured out!
She's in a coma of something! She's just dreaming all this wierd crap. when her boyfriend calls her on her cellphone he's really talking to her unconcious body at the hospital.. and the other guy she hears on the phone is the doctor. and when she's spinning around grabbing her head while everything is freaking out.. there's the sound of sirens from ambulances and it shows her on the ground covered in blood.
Am I right? O.o... well w/e this movie was great. I can't wait for more!