The Alternative Factor - S1-E28
Continuity mistake: Both the positive and negative versions of Lazarus have a long mustache and a fairly full "waterfall" beard - until the scene in the briefing room, when inexplicably, the mustache and beard are both suddenly so thin they're barely visible. As soon as they beam down to the planet, however, the much thicker facial hair is restored. (00:23:00 - 00:24:30)
The Alternative Factor - S1-E28
Continuity mistake: Lazarus had knocked out the transporter technician, but when Kirk arrives he is fine and operating the transporter. (00:37:35)
The Alternative Factor - S1-E28
Continuity mistake: Mad Lazarus has just put a black-and-white hatch cover over the stolen dilithium crystal in his time ship. It's in place when Kirk arrives to confront him. But a moment later, when Kirk leans in and is accidentally transported to the negative universe, the cover has disappeared. It's still missing when Kirk returns to push Lazarus through the portal. (00:39:20)
The Alternative Factor - S1-E28
Continuity mistake: Kirk keeps referring to Masters as "Lieutenant", even though she has no braid on her sleeve - all Enterprise lieutenants have a single gold braid on each sleeve.
The Alternative Factor - S1-E28
Continuity mistake: Lazarus' goatee and facial injures are constantly changing.
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