Audio problem: When Michael is forced to do "errands" for Brennen, they stop by Jonathan Carver's house to get numbers from him for a voice key. The code played back at the facility is 71348. He says "3" in a medium pitch (tone) at the house, but it is high pitched when played back at the facility; he says "8" in a medium pitch, and it's also high pitched later. And finally he says "9" in a low pitch and it's played back medium pitch. Also very obvious is the fact that Jonathan never says "1" or "7."
Continuity mistake: During the scene when Michael is attempting to deceive Brennen into letting him and Nate go (from the time Brennen receives the picture message to when Brennen leaves), Brennen's necktie (right below the knot) changes from having a dimple to being flat, 6 or 7 times during the scene.
Character mistake: Near the end, when Michael reveals to Brennen he knows everything about him, he says, "I know everything about Tyler Brennen." Michael emphasizes "Tyler" as if it's a big deal that he knows Brennen's first name. Michael already knew Brennen's first name from the first time he met him, in Season 2, Episode 15 "Sins of Omission."
Continuity mistake: Michael makes the target/client use a faulty pen that spill ink all over her hand. When Michael is in the bathroom and holds over the targets mouth, his shirt gets dirty of the ink from the target/clients hand. After this, it switches between the shots and Michael having a dirty and clean shirt several times. (00:10:53 - 00:11:46)
Factual error: When Michael attempts to start the Charger, the starter just clicks, indicative of a dead battery or faulty starter. He checks his father's logbook and reads "spark plugs." Unless the cylinders are filled with an non-compressible liquid, there is no way that spark plugs are going to prevent the engine from cranking.
Continuity mistake: Michael is having a meeting with the guy who is asking how Michael found out about him (where Sam is standing guard with the sniper rifle.) Michael has a gun pulled on him and is trying to escape. As Michael is trying to leave in the Charger, he pulls backwards and makes a 90 degree turn so that the passenger side of the Charger is facing the guy with the gun. The windshield could not have been shot from this angle. The next camera shot Michael is driving backwards again with the windshield facing the guy so he can shoot a hole in the center of Michael's windshield.
Continuity mistake: Just after Michael throws his mothers cigarette out of the car, there is a shot from the inside through the front window. There is a large crack in the glass, bottom left of the rear view mirror. When the car is shot from the front, there's no crack. (00:24:30)