MAKO. OH MY GOD.
She clearly has a relationship with the senpai this droid is impersonating. (And I’m shipping it, maybe one sided maybe not.) But they weren’t close enough for cute nicknames and Mako clearly doesn’t think they’ll get to that point because that’s what alerts her. 
My poor girl, figuring things out because she knows too well what to expect. 

I’ll definitely come back to this moment when I can be more coherent.