When Paris is exiting the vault, the combination lock is at 10 and he turns it back to 8. As he exits, the lock is set back at 10.
After Jim gets his instructions and stops the tape player, there is tape on both reels. In close-up, for the self-destruct sequence, all the tape is on the take-up reel.
Paris and crew are to counterfeit 1 million, 100 Drona notes in approximately six hours. This would require printing more than 46 notes a second. The press being used is not even printing one per second.
The counterfeit note shown in close-up at the episode's denouement used the halftone process, employing regularly spaced dots. However, to be more difficult to counterfeit, banknotes use a manual engraving process that uses line thickness and spacing to modulate lightness.
The frequency mentioned for the ultrasonic barrier is 3 million cycles (3 mHz) which is in the radio frequency spectrum (shortwave above the AM broadcast band) far above any type of sonic spectrum.