Senator Davis says this to Stringer when String tries to coerce him into speeding up the development of B+B Enterprises. What he means is that the legitimate, political world is not like the streets. You have to set up a foundation, build relations, and pay off the right people to be successful, whereas in the street you can just take what you want. It’s not what String was hoping to hear.

Horseface says this to New Charles while he’s waiting for an ambulance after suffering a bad leg injury on the dock. This quote shows the camaraderie of the union, as they are all willing to make sure their brothers get every last cent and benefit available to them. It is also a darkly funny commentary on the state of American unions – it’s almost worth it to shatter a leg while on the job because hours are so hard to come by.

Officer Colicchio uses this term to describe Colvin’s “Hamsterdam”. While many characters, and by extension the show’s creator David Simon, feel as if scaling back the War on Drugs and resisting the temptation to throw these dealers in jail is a good idea, Colicchio’s view is the old school opinion from the opposite end of the spectrum. In his eyes, drug dealing should be illegal, police should make arrests, and drug dealers should get beaten or thrown in jail – it’s as simple as that.

Brother Mouzone speaks of reform in this episode when he sees that the Towers, symbols of the Barksdale reign, have been knocked down in favor of real estate development. It’s strongly hinted that Mouzone is cynical of the possibility of real reform, and he is backed up by the fact that Bunny Colvin’s attempt to reform the War on Drugs this season showed promise but failed.

http://screencast.com/t/49OtirCS1lo

It also refers to Cutty’s personal reformation, which is more successful, as he is able to leave the game and open his gym.

This refers to various characters' attempts to get their life together and become more legitimate:

• Stringer continues pushing B+B Enterprises forward in hopes of becoming a legal organization soon
• Cutty is beginning to realize the street life is no longer for him, and eventually goes on to open his boxing ring
• Bubbles wants to stop scamming to get by and make his money by working with the police as an informant

This phrase pops up three times this episode:

• First in the opening sequence, to Omar when he is robbing a Barksdale stash house
• Next by Shamrock to Stringer during a chair meeting when he respectfully disagrees with his executive decision
• Finally, by Burrell during a dinner meeting with Carcetti when he is trying to kiss up in exchange for sending resources to the police department

All three times speak to the importance of hierarchy in this show – whether it be official like Burrell/Carcetti’s encounter, or merely based on respect like the way the stash house boy treats Omar – as well as the importance of obeying said hierarchy unless you want to get slapped down.

“Backwash” continues the nautical theme of this season’s titles, but it refers to metaphorical backwash, not actual waves. D'Angelo brought up how events from your past are inescapable and often come back to get you in the last episode, and this holds true here. Frank’s dealings with The Greek prove to be a problem he cannot escape, and it catches up to him by the end of the season.