Continuity mistake: Mike yells at Jessie to make himself useful and find a gun. The shadows in these two scenes are very long indicating it was shot late in the day. In the next shots and rest of the sequence, the sun is overhead.
Continuity mistake: While Gus speaks with Eladio beside the pool the sun changes on the floor between shots.
Continuity mistake: After Gus goes to the restroom, there's a shot of the cartel leader smoking a cigar as he turns to look at Jesse. The cigar is burnt down nearly to the band around it where his fingers are. When it cuts to a different angle to him taking it out of his mouth, suddenly there is much more cigar left above that band.
Continuity mistake: There is an X on the back of the black Hummer during behind shots. It disappears approximately 10 seconds later.
Crawl Space - S4-E11
Continuity mistake: In the opening scene, the medical team is treating Gus. The oral syringe of medication is drawn to "1", in the next scene, it is completely full when the man administers the drug. (00:01:20)
Crawl Space - S4-E11
Factual error: When the doctor is reciting Jesse's medical information, he states that he is 1.87 meters, which would make Jesse 6ft 3 in. Aaron Paul is only 5ft 8 in. (00:07:42)
Suggested correction: First, the doctors says 180 centimeters, not 1.87 meters. 180 cm is 5'10." But it's not a mistake if characters are a couple inches taller or shorter than the actors that play them. Just like often characters can be older or young than actors that play them.
Crawl Space - S4-E11
Visible crew/equipment: A camera in a black protective box is visible on the ground in the intersection during the crash sequence when Walt gets T-boned by an SUV. (00:24:48)
Crawl Space - S4-E11
Continuity mistake: Ted is in his house with Saul Goodman's men. When he beats his head on the furniture after he stumbled on the carpet in attempt to escape and passes out, his legs change position in two different angles shots.
Crawl Space - S4-E11
Continuity mistake: In episode 2-10, Walt installed a new gas water heater. The gas lines run from the left wall to heater mounted on the back wall of the utility room. In episode 4-11, Walt is in the Crawl Space under the utility room. The gas lines are no longer visible.
Continuity mistake: When Gus walks towards the nursing home towards the end of the episode, two flags in the background stop waving, but in the next shot they suddenly wave again.