Steven Bauer says in the insider podcast that he had to psyche himself up for the scenes with Mike (Jonathan Banks)in this episode because when Jonathan is in character, he has this scary presence that is very serious and somewhat intimidating.
At the end of the episode where Jesse shoots the last member of Don Eladio's gang, Vince Gilligan asked editor Kelley Dixon to make Jesse's shots appear faster, so she spliced out the milliseconds in between shots to make them feel overlapping and faster. You may not have noticed it while watching the first time, but if you review the scene, the slices are clearly evident when taking a closer look. However, it's barely noticeable if you are taking in the full scene. Kelley Dixon also couldn't do the effect with sound, so they later re-added the sounds in.
Regarding the pills that Gus takes, the team researched and found "activated charcoal" tablets that apparently can soak up poison and help delay the actions of it.
No tequila company would let them use their booze as poison. The tequila bottle was an antique that the prop crew found at an antique store. The crew hand-crafted a box for it. According to Steven Bauer, the bottle was also incredibly dangerous, he cut his hand three times with it while filming. They only had one bottle and they couldn't replicate it.
Michelle MacLaren notes in the insider podcast that the Mexican drug lab was a closed down power station and the production designers worked to transform it into the large methlab scene. The crew only had one day to film there.
The location of Walt's apartment is actually owned by Vince Gilligan
This episode required a second unit film crew because shooting did not fit within the 8 days allotted for the 10th episode. For the plane scenes, they required clearance for the takes involving taking off and landing from the FAA. It was also windy so some of the planned shots had to be rethought.
Carlos Rota (Cartel Chemist) actually has a British accent, so it's interesting in that he has to mask this with a Spanish one and then talk normally in English soon after.
Skyler: You can't come to my work like this, you're too recognizable. Your face is plastered on every bus bench within a 5-mile radius.
Saul Goodman: Celebrities have to get their cars washed, just like everybody else.
Jesse: (Aside to Gus) Look, I get my phenylacetic acid from the barrel with the B on it. That's how I do it.
Gus: (In Spanish) Mr. Pinkman was under the impression that the phenylacetic acid would already be synthe upon his arrival.
Cartel Chemist: Any sophomore chemistry student could make it. What kind of amateur have you brought us?
Jesse: What did he say?
Gus: We're working it out.
Cartel Chemist: This is ridiculous. I'm not letting some infant who can't even synthephenylacetic acid teach me my business.
Jesse: Tell this asshole that if he wants to learn how to make my product, he's gotta do it my way. The right way.
Cartel Chemist: I speak English.
Jesse: So you understand what asshole means. Now go get me my phenylacetic acid, asshole.
Walt: I made a mistake. It's my own fault, I had it coming. It's all my fault. I'm sorry, I'm sorry.
Don Eladio: Gustavo, cheer up man. Gustavo, I'm not angry. I had to spank you. But what choice did I have? Look, once every twenty years you forget your place. There's no place for emotion in this. You of all people should understand. Business is business.
Cast: Dean Norris (Hank) and Betsy Brandt (Marie) are credited but do not appear.
Michelle MacLaren uses the 180ft crane again in a camera shot from above Don Eladio's estate.