SPOILER Noreen
SPOILERS BELOW ABOUT THE PLOT AND ENDING
So, once Noreen kills Smith and leaves the diner with the cash, do you think she gets away with it? The only people that know about the cash are dead. I'm assuming she left town or the country and enjoyed the money in Mexico or somewhere else.
It would be interesting to see how the local police or possibly the FBI puts together the incidents of that night. Do you think Smith's associates would even bother trying to track down Noreen since Smith wasn't the only one killed? Plus, Smith's "family" doesn't even know if money was ever delivered nor would they really know (or probably care) who really killed Smith.
Even though Noreen left prints on the knife and the gun would the police or FBI look for her? As far as they know, she killed Doe (from the prints on the world's sharpest steak knife) flipped out in shock and disappeared from town.