Near the end of the movie when 'Carl' breaks into the house and ends up shooting the husband, you see that he is shot in the chest. Then afterwards you see him at home wearing a sling making you believe he was shot in the arm.
At the end, Elaine is talking about the sentencing hearing and Cooke getting 2-7 years. In federal court, sentencing hearings take place 75-90 days after a conviction. Cooke then talks to the media and announces a new website. He then says to Elaine and the group of victims he is fighting the false charges. If they were there for a sentencing hearing, then he would have already been convicted . It appears Cooke had not been convicted at that point.
A person convicted of a felony in federal court once sentenced to prison is taken into custody immediately afterward. Cooke would have been in custody and unable to launch the final attack shown.
The fight scene at the end had Elaine standing by helpless while David was fighting Cooke, which was completely contrary to her character. She then got involved after David was shot and temporarily disabled Cooke, yet left he gun within reach of Cooke. Cooke then made a similar error by not picking up the gun right away. Seeing as how he had already shot David he would have no hesitation to shoot Elaine and Peyton.
The officer making the traffic stop says the car had a tail light out. The car was being driven in the daytime and did not have its lights on. Since the lights were not on, the officer would not know if the tail light was out.