Question: While Jack and Tel'c are stranded in space, Maj Carter talks to them via the long range radio, when she finishes she gives the time and then Zulu. What does that mean?
Answer: Zulu time is another name for Greenwich Mean Time, often used as a worldwide time standard.
Question: The sound of the Russian submarine's engine at the beginning seems to subliminally mimic the steady tension-inducing beat of the replicators' theme music, and is occasionally overlaid with a variation of the two main higher notes that are usually played by horns but are played by strings in this instance. I wonder whether this use of the engine sound in place of the normal "replicator beat" was intentional - or perhaps just my imagination?
Answer: As there was no actual engine noise, (it's all added in post production), this was likely done deliberately.
Question: Why couldn't Calder and his people do the shoveling themselves? Were they lazy?
Answer: Technically Calder's people were doing the digging themselves. The planet basically had a caste system and the working class citizens had to do the digging as slaves while the upper class citizen got to live on the surface. All the workers underground were citizens of the planet except for SG-1. However, Calder was also trying to preserve this caste system because he wanted to stay in power and the upper class enjoyed their lifestyle. I don't see it so much as being lazy but more like, why do something yourself when you can get someone else to do it.
Then what would you call being lazy?
Laying around, not doing anything when you could be, or are suppose to be, doing something. In this episode, the upper class people still had jobs, they just didn't do the dangerous, dirty, and labor intensive jobs.
Answer: In almost every gangster move from the 1930's, there was always a guy named "Rocco." A dumb but lovable guy who always agrees with the Boss. When everyone disagrees, he always says "Listen to the Boss." or "Do what the Boss says."