A few purchases go down in this episode:

• Sydnor goes undercover to buy dope from one of Avon’s soldiers, Bodie
• We learn more about the Barksdale drug trafficking system in general
• And Valchek buys Prez support in the wake of his towers disaster by using his influence to sway Daniels

This refers to the newly formed police detail led by Daniels formed in order to pursue Avon – McNulty, Freamon, Greggs, Prez, Sydnor, Polk, and Mahon.

It could also refer to the close attention the show pays to details.

Ronnie says this after Clay Davis' trial, in which he relied much more on invoking an emotional response from the jury and judge than traditional legal defense.

https://www.youtube.com/watch?v=bAQv6KTfQow&feature=kp

This could also refer to The Wire’s tendency to operate outside the law, e.g. Colvin’s legalized drug zones, McNulty’s fake serial killer, and Ronnie seducing Judge Phelan to get wire taps approved.

This is the first episode that forces the viewer to realize that trying to take down a high-ranking drug organization isn’t all fun and games. Up to this point each episode showed the Major Crimes Unit getting closer and closer to Avon without retribution – it was beginning to look like your run-of-the-mill cop drama where the good guys get to win because they work really hard.

But in this episode Kima is shot, almost fatally, for her involvement in the investigation against Avon Barksdale. Her injury is the MCU’s cost of rejecting stat-juking and safe cases in favor of real police work.

Lester says this to Prez to emphasize that every call recorded on the wiretap is important if they’re to build a case against Avon, but this quote is also hugely important in the context of the entire show.

First off, The Wire has a pretty complicated plot. There are plenty of minor characters that don’t get much screen time, but are still essential in moving the plot forward. So if you don’t pay attention to these minor events and characters, you may be confused as to how the show arrives at its grand finales. Secondly, one of the main goals of the show is to demonstrate that everything in the city of Baltimore is intertwined – from the dealers, to the police, to politicians, to the schools, to the journalists. So while an event may only appear to affect one section of the city at first, it is most likely going to have a greater impact than it first appears.

And if we’re going to continue the chess metaphor this show loves to use, this could also be interpreted as a reminder that even the most insignificant chess pieces (the pawns/soldiers) can have an impact on the course of the series.

Prop Joe says this to Andre in his pawn shop after tinkering with an electronic device. He feels the repair-cost of electronics is too high, and oftentimes you’re better off just replacing the device. The full quote is

“Some people would think, for what it’s worth, to fix it and make the shit work right, you might as well dump them and get another.”

The full quote refers to Joe’s suggestion that Andre cut his losses, sell all of his assets to Joe on the cheap, and start his life anew before Marlo can get after him. But the snippet in the epigraph refers to how drug organizations – Marlo’s in particular – have no problem with getting rid of people that are either a liability or no longer essential to the organization’s success.

This was demonstrated by the Barksdale organization when they “dumped” Wallace, when Avon allowed String to be killed, and when String even put a hit out on Senator Davis (sheeeit!). It’s even more prevalent with in the Stanfield organization, as Chris and Snoop, on Marlo’s commands, kill rival New York dealers, Little Kevin and Bodie when he fears they are snitching, Old Face Andre, and, ironically, Prop Joe himself.

McNulty says this to emphasize that he isn’t going to make things easy for Baltimore Police Department homicide after they booted him to the marine unit. They punished him by sticking him on a boat, but now he is making their lives hell by going out of his way to dump unsolvable murders on the department.

This also suggests that even though they are mad at him now his punishment will eventually come to an end, which proves true when Rawls reluctantly allows him to help out the Major Crimes Unit.

The name of Season 3’s most important development is actually the result of a misunderstanding. When local drug dealers listen to Herc comparing Colvin’s new “legal drug” zones to Amsterdam – a Dutch city where most drugs are legal – they mishear it as Hamsterdam and begin calling it that.

Some have suggested that the writers choosing Hamsterdam in favor of Amsterdam suggests that the dealers feel as if they are hamsters being observed by the outside world, but it’s just as possible that it’s intended as a joke pointing out how little these dealers know about countries outside of America, or areas outside of Baltimore for that matter.

“Undertow” is commonly (but technically incorrectly) used to describe a wave that traps swimmers and pushes them underwater until they drown. This references Frank’s inability to distance himself from The Greek despite realizing the harm it could bring to him, as well as other characters unable to remove their self from bad situations in this series, such as McNulty and homicide.

Spiros says this while looking at the bay to suggest Frank would be unwise to stop working with The Greek even after finding out the police are looking into him – keyword used to. He is hinting that America’s manufacturing/manual labor jobs are no longer important, and Frank’s only hope of keeping the dock alive is through his illegal dealings with The Greek.