Doctor Kruipen called the parasite vertebrates, which the students read from the doctor's notes. They were later called bugs by the same students. Bugs are invertebrates. Then the student said " They're vertebrates, they're not bugs."
(At around 42 mins) After Jane dies and everyone leaves the room, there is a medium shot of her lying in bed with her face and neck splattered with brown goop. The reflection of light off the goop on her neck shows her carotid artery is still pulsing.
From the door of the tent, Jane fires her rifle at point blank range, hitting her target standing just outside the tent, but the sound of her gun comes after her target is already hit.
Vertebrate was misspelled as vertibrate (on Kruipen's notebook) considering Dr. Kruipen was a research scientist.