As she is being kidnapped, the abductors wrap Renee's face/head in tape. Before placing her in the van there is no tape across her nostrils and they are visible. Once in the van, her nostrils are fully covered. The following scenes of her in the van show the tape in various positions on her nose and face. Almost slipping off her nose one moment and then up to the bridge of her nose in the next.

And if the amount of chemical injected didn't kill her, the amount of air put into her bloodstream surely would have.

The quantity of the chemical shown injected into the protagonist would have killed her. It was simply too much volume for anything except a saline solution and would have resulted in anaphylactic shock and death.

The snake used to terrorize Blake is a breed of python. While pythons do have teeth, they are very tiny, and they do not possess fangs. Snakes with fangs rely on venom to kill their prey, while pythons are constrictors. They have no need of such fangs.

SPOLIER: Renee kicks out the AC vent into Blake's cell, she leaves the gaping hole and vent grille on the floor. The next scene three captors enter the room and engage in a lengthy conversation. No one notices the grille on the floor, or the open hole in the vent.

Blake mispronounces Nevada. If he was actually from a small town like Elko, there is no way he would pronounce it wrong.