The racism and lack of professionalism of the crew under pressure is apalling, but it was a running theme in the early season one episodes. It's worse when you consider that the really whiny ones are not youngsters but quite senior officers.
Mears keeps a level head but as is often the case for the poor yeoman, she does almost nothing useful, being required only to record stuff. Rand was originally intended to be in that role. I know her early character draft was to have a sisterly relationship with Spock that we never really saw in any of her episodes. I wonder if she might have been a bit more supportive if she had been featured.