That's not really so clear and there's really no need to get agitated about it.
Maybe they wanted to use the "left of Spock" section for the camera as you posit, but it's strange that no one said, "Hey, why don't you just have one of the Kelvans (I think it's Rojan who shrinks Chekov) make like they're stepping off to the right, then shoot Walter from his right like the series has done countless times to date."
Also, I'm not sure it would have been impossible to take a shot of Walter at his station from the area of the captain's chair or behind it without removing everything.