Star Wars TCW: 3x18-20

at 40:40 ish, That definitely was the imperial march theme, the part b you were waiting for is super delayed and slowed so it just sounds more like ambient noise, but yes imperial march to signify anakins doubt of the jedi and his descent, good catch

1:11:15 "it matters not the quantity of your emoting, but the quality" - Abraham Lincoln (probably)

during that scene you showed from a new hope of Vader force choking that guy and Tarkin tells him to stop and Vader listens not just because he respects Tarkin but because on the first death star Tarkin was in charge of everything, the emperor told Vader that when on the death star a command from Tarkin is like a command from the emperor himself.

Fun Fact the guy in the white uniform during that table scene in A New Hope is Admiral Yularan. Aka Anakins Admiral who is always fed up with his antics.