Kill Switch - S5-E23
Other mistake: In episode "Kill Switch" it states that Jason Billings died from a broken neck, it shows Tony Decker kicking him in the face snapping his neck. Jason then tries to claw his way up onto Tony's deck leaving the scratches and blood and getting the splinter under his nail. This wouldn't have been possible since he would have already been dead.
Other mistake: When Eric is shot in the head they show you in slow motion him going down, he was shot in the left back of the skull, their would have been some blood spatter on the car and there was none.
High Octane - S5-E7
Other mistake: When the guy's head is cut off, his arms are up in the air next to his head. Yet his head is sliced clean off while his arms remain intact. And they would not have gone slack and fallen down after his head was cut off because they are right next to his cheeks (and the car was moving way too fast to allow for that anyway).