Character mistake: When Hank is brought to the hospital with gunshot wounds, the ambulance and its two EMTs are met outside by two doctors. One doctor says "Let's get him two grams of oxygen. What's his hemoglobin?" This episode's technical adviser was perhaps away for this scene. How much exactly is two grams of oxygen? Orders for administering oxygen would be given in liters, such as two liters per minute (LPM). The line is presumably meant to be 'two liters of oxygen'. (00:02:25)
Factual error: The final scene of the episode, the cousins are hiding with other migrants amid a farm truck's bales of straw. One of the migrants claims they are in Texas. However, the mountains in the distance are the Manzano Mountains which are just several miles southeast of Albuquerque, more than 200 miles away from the border with Texas and Mexico. The migrant claims he has gone through this route 3 times, so it is unlikely this would simply be a character mistake.

Green Light - S3-E4
Continuity mistake: In the scene where Walt is talking to Jesse in Jesse's car, when Jesse pulls out the bag of meth it is in a slide to seal bag. The bag changes between this and a regular ziploc bag from shot to shot. (00:19:30)

Continuity mistake: Mike Ehrmantraut takes Jesse to a house in the desert. He pulls up behind a dark blue car, which vanishes in the next shot, and then reappears.
Other mistake: Gus is talking to his employee about the twins while writing something on a clipboard. However, he is using the opposite end of the pen and just pretending to write. (00:14:40)
Green Light - S3-E4
Visible crew/equipment: When Hank pulls up on the side of the road to answer his phone, the camera crew are reflected in the Jeep's grill. (00:31:00)
Visible crew/equipment: When Walter is sitting on the bed looking at the doll's eye ball, a lighting screen is reflected on it. (00:31:00)

Green Light - S3-E4
Continuity mistake: When Mike gets out to throw Walt into his car the back passenger door is shut but when he throws him in it's open. (00:08:35)
Continuity mistake: When Jessie, Victor and Mike pull into Gus' chicken plant they pull up behind Gus' car, but when they get out the car is gone, and when they start to walk to the building the car is back.
One Minute - S3-E7
Factual error: As demonstrated in the earlier scene where Leonel shot the truck driver/arms dealer, bulletproof vests do not make the wearer immune to bullets. Bulletproof vests are only designed to stop penetrating injury- they do not counteract the high energy of an impacting round, which can easily break ribs and cause internal injury. When Hank empties Leonel's dropped gun into Marco, Marco is barely staggered despite the fact that he just took five rapidly fired bullets in quick succession to his upper chest. That many hits at such close range in such a small zone would have, at minimum, shattered several of Marco's ribs and potentially punctured one or both of his lungs - both critical and incapacitating injuries on their own. As a result, Marco should have been unable to lift his gun to shoot Hank twice in the chest, much less swing an axe. Additionally, at least one bullet appears to strike Marco's clavicle and upper shoulder- both areas that are not protected by the vest. (00:44:00 - 00:45:00)
Suggested correction: Bullet proof vests disperse the energy of projectile impacts. Bad bruising can result but certainly not broken bones or punctured lungs.

Green Light - S3-E4
Continuity mistake: When Hank is standing between the ATM and the pumps at the gas station, the shadow cast by the roof over the pumps shifts between shots. The shot from away, taken next to the pole with the Indian logo was taken earlier in the day, casting a long shadow. The other shots have a higher sun which has moved by several hours.

Continuity mistake: When Gus is showing Walt the lab, the washer leans forward with one item hanging out. Camera cuts and 2 items are hanging out. This is an instant cut and no time for the item to fall into the position. (00:21:20)
Continuity mistake: When Walt throws the pizza on the roof, it lands 5 rows up from the edge. When the camera cuts to on the garage roof, it's only 3 rows up. Also the amount of topping changes between the angles. (00:34:30)
Visible crew/equipment: During the shot from the interior of the car of Hank following Jesse, a camera man in a green T-shirt can be seen crouching down on the road to the right of the screen. (00:30:40)

Continuity mistake: When Walt is talking to Saul near the start, we see him unbalance the scales on the table in front of him then lean back. Camera cuts to Saul for a few seconds then shows Walt from behind Saul. In this angle, the scales are now balanced. (00:16:50)
Continuity mistake: Gus invites Walter over for a meal and we see him wash an orange pepper and some celery and place it to one side. It reappears in the sink a second later. (00:39:30)
One Minute - S3-E7
Continuity mistake: When Hank finds out Jesse may not be pressing charges, his tie moves without anyone touching it. (00:38:45)

One Minute - S3-E7
Continuity mistake: During Hank's interview, the tape recorder is constantly disappearing and reappearing on the table. (00:15:20)
Continuity mistake: While Walt is out of his car and arguing with the police officer, there are other cars visible in the far distance behind him. The cars appear and disappear in between shots, there isn't time for them to pass and we don't hear them pass. (00:03:30)
Continuity mistake: At the beginning of the episode Jesse and Jane leave the art gallery and go to his car. From the outside, Jesse's car is right up close to the Porsche in front, but the inside shots show they are about 4-5 feet back from it.
Suggested correction: He could have just been boasting, whilst not actually knowing where he is. He is just a kid after all.
lionhead
Worse than all of that, is the fact that you can't get directly from Mexico into Texas without traversing a river. There are no land routes.
There are no bridges?
lionhead