Paul McGillion plays the role of the young Ernest Littlefield. He later plays Dr. Carson Beckett in Stargate: Atlantis (2004).
The Torment of Tantalus. In ancient Greek mythology Tantalus was a demi-god welcomed into Olympus, the home of the gods. He repeatedly misbehaved, most notably when he cooked his son Pelops and tried to serve him as a meal to the gods. His punishment was to eternally stand where both food and drink moved to stay just beyond his reach; hence the word 'tantalise'.
In the 1945 flashback, Young Littlefield is telling old Langford that the Stargate symbols are not a combination lock but destination symbols. At this point Langford lights his pipe using a Nimrod pipe lighter, 1945 was two years before Ashley Ward, Inc. patented it and put it on the market. By the mid 60s, about a million Nimrods would sell each year.
The DVD episode order differs somewhat from the broadcast order. This was the tenth episode broadcast, but is Episode 9 from Volume 3 of the Season 1 box set.