Continuity mistake: When the 6 News begins it's broadcast, Karen is seen passing the camera and walking over to the news desk. It cuts, then goes back, and Karen now walks past and towards the desk a second time. (00:17:35)
Other mistake: At the end after the barn fire, Marcia is at a tavern, ordering a rare steak. While it is believable that she escaped the barn fire, it is unbelievable that she is in the tavern wearing the same dress and necklace she wore prior to her transformation in the barn. All of her attire would have been rended in the transformation and lost in the fire. Unless her wardrobe consists of duplicates of the same clothing.
Revealing mistake: The final shot of the sex-scene between Bill and Marsha is very obviously a piece of (rather cheap-looking) 2D cell animation. The actors look like cartoons, the fire is simply the same few frames repeated over and over and the background looks obviously painted.
Factual error: The rifle which Dennis Dugan's character is using has to be reloaded before every shot. Still, when he shoots Slim Pickens, he somehow manages to hit him with two bullets within a second.
Continuity mistake: Terry drops the phone on the floor, so that it hangs from the desk. The telephone cable is long enough to allow it to reach the file cabinet without being too tensed. If she dropped the receiver there, the cable would not retract so much as to leave it hanging from the desk. (01:00:45)
Visible crew/equipment: When Karen enters the phonebox with the yellow smiley sticker inside, you can clearly see the cameraman in the glass of the phonebox, as he pans round. (00:03:25)
Continuity mistake: When the female reporter is scared by the dog, she whacks the dog with her book, which then flies out of the window. In the very next shot the book is suddenly back on the table. (00:14:55)
Continuity mistake: When Fred Francis is at the control booth, his stance changes between every shot, from standing up straight, to bending over, with his leg up, then down, etc. (00:09:35)
Audio problem: When Eddie is talking to Karen in the pornography booth, while the film is playing, what he is saying frequently mismatches his mouth movements. (00:10:05)
Continuity mistake: When werewolf Eddie takes the file from Terry's hand, while she's on the phone, the phone drops from her ear, to the floor, twice between shots. (01:00:45)
Answer: I think they were purposely brought there to both join the colony. Marsha, who desired Bill, was impatient and bit him. As for not being mad at her, the Colony was slowly turning to her leadership, instead of the Doctor's compassion treatment.