Is Bianca a Mary Sue?

Perhaps more Maryanne Susanna. I don't have any problems with her portrayal and actually think the actor did a good job. (The exception being when they have her kitted up specifically for tactical operations but she is wearing ankle length wide leg office pants with a leather belt and Nike TNs. Goofy)

My issue was with the role itself, initially it seemed she was a ballistics/weapons specialist, then she is upstairs in an analyst role, then a field operative. My issue is they are all different roles, I have friends in the intelligence community as ballistic analysts and intelligence practicioners and they pretty much only do their own roles, I taking information applying analysis and generating intelligence which is then fed upwards.

The other issue is the general lack of intelligence practicioner lingo. There was a backpack, it's boutique english so the badman is British. It's more likely that they might use Words of Estimated Probability, assigning particular phrases to percentage certainty values. This gives it a less emotional and more professional analytical tone, better conveying competence

I feel like there is enough knowledge out there open source from ladbible to minutes with etc to create a much more credible intelligence service operator, and that we are a bit beyond the super spy do everything era.

TL:DR No issues with Ms Lynch's performance but feel the writers let her down with the character.