I think the dog (Watson) may have been tasered, you don't see or hear it happen, you just see him lying on his side for about 2 seconds. Watson survives and is well!
A kidnapped woman has her mouth taped over around minute 46. Earlier in the film, an audio recording of another kidnapped woman plays; it is implied that her mouth has been taped shut.
There are several potentially triggering scenes. A few women are abducted, raped, tortured in this film - it is a central part of the storyline. There is an audio recording of one assault played on a tape recorder, it's pretty awful, I recommend skipping that part. There is also a scene where a woman is assaulted in the back of a van by two men, who are also recording a video of the assault. It's more confronting than I was prepared for. Proceed with caution.