The Russian submariner, before opening the torpedo tube, answers his comrade's question: "What do you think is in there?" He actually says (in Russian): "Maybe it's a bug from previous episode!"
The submarine was a Soviet/Russian Foxtrot-class number B-39. It had been decommissioned in 1994 and was stored in Vancouver from 1996 to 2002. It became an exhibit at the Maritime Museum of San Diego in 2005. In 2021, it was withdrawn from the collection and subsequently scrapped.
One of the Russian submariners is actually speaking in Ukrainian.
Major Davis informs Daniel that the Dallas is standing by to torpedo the Russian submarine. The U.S.S. Dallas is a real, Los Angeles-class nuclear-powered fast attack submarine. It is notable in that it was featured in the Tom Clancy novel and hit film The Hunt for Red October (1990). The Dallas was launched on April 28, 1979 and decommissioned by the Navy on April 4, 2018 making her one of the longest actively running submarines in US Naval history. As of January, 2019 the Dallas is docked in a mothball fleet, though there are plans to make the Dallas a museum ship, if and when funds can be raised to do so.
The other Asgard that appears on the screen behind Carter is just repeating the exact same lines (in Asgard) said between the two Asgard in Season 2's The Fifth Race (1998).