Visible crew/equipment: After Kirk hits Kras with an arrow Spock's arrow hits a Capellan on the cliff, and when the Capellan falls into the bush, a crew member wearing sunglasses and a white T-shirt is visible at the left side of the screen. (00:43:50)
Continuity mistake: When Kirk's arrow hits Kras it protrudes from his leg, but in the next wideshot as Kras screams and stumbles the arrow is quite gone from his leg, but three shots later the arrow is back in his leg while he tries to pull it out. (00:43:40)
Chosen answer: If they're in orbit, they're being pulled along by the planet's gravity well, therefore, impulse engines would only be used for minor corrections and would be "on standby" while in orbit, but not active. (Like keeping your car idling without revving the engine and creating plumes of exhaust).
Captain Defenestrator
Thank you for the info.
Movie Nut