Suki is a young woman confronting her destructive mental illness using "The Siamese Burn," an experimental machine designed to eliminate multiple personalities. The closer Suki comes to being "cured," she's haunted by a thought... what if the last unwanted identity turns out to be her?
There's a scene around 41mins in (I didn't get the exact runtime) involving the dog that's pretty awful and leads you to believe the dog has been killed, but shortly after the dog appears again and makes it to the end of the film without any visible harm. Still, I'd recommend hitting mute for that particular scene in which the character hooks the dog up to the machine. Visually you can see the scene coming and then it happens off screen, but there's audio that includes whimpering and howling that can be unnerving.