During the 24-26 minute mark when the 2 actors (serial killer and cop) get pulled over, after undercover agent Paul Briggs gets out of the car the red and blue police lights can be seen flashing on the motorcycle. However, when he gets on his knees - per the bike cop's request - they aren't flashing, and when he is tased and laying on the ground the lights are not flashing. Then, after asking him a question, the lights on the motorcycle are flashing once again.
When Mike presses the button to administer pain medication (likely morphine) the camera zooms in on his eyes and we can see his pupils dilate considerably and rapidly as the drug takes effect. However, opiates like morphine and heroin constrict the pupils. Instead of being blown wide like saucers his pupils should be tiny like pinholes.