Agreed with others that this feels out of place with the rest of the series. There had to be a better way to explore Mitsuki's self doubt than bullying like this.
One thing I do think is done well is how the use of the green accent color drops away to pure monochrome when it is happening. The only flash of color we get is a quick Aya face interjecting itself into her thoughts.
I woke up today in a oneshot kind of mood and found this one exploring a kind of relationship that doesn't get much representation in media. I really enjoyed the nuances in how Morita dealt with her coworkers/boss and how they were trying to be supportive in their own ways but still ended up causing discomfort/confusion in Morita.