So, Chapter 3. I've been setting up the fight between the Sergeant and Fate for long enough. Now, we get to see it actually happen.
Spoiler alert: the Sergeant loses. Badly.
I mean, I never envisioned any other option here. Either from a tactical, in-universe perspective, or from the perspective of an author trying not to create a Mary Sue OC, there's no way I can let the Sergeant actually defeat Fate in a fair fight. (Although I may be trying a little too hard on the latter count.)
Miku's MRS is a powerful advantage, yes. As the Sergeant has figured out, it somehow acts as an amplifier, removing the Sergeant's lack of power as a tactical concern. However, it has a number of significant weaknesses as well. Time, for one thing. The one song that Miku has available to her right now clocks in at 3:34. By starting "before" the battle began, Miku and the Sergeant were able to finish in time for it to be relevant, but the possibility of avoiding Fate's attacks for another three and a half minutes might as well be zero.
Accessibility is another. I did say "one song" after all. The power boost is significant, but right now it is also purely defensive. It won't stay that way forever, but right now the Sergeant has no offense worth mentioning. As Fate demonstrates, that's no way to win a fight. The Sergeant tries, of course (primarily through intimidation rather than naked power), but really he was doomed to failure from the moment Fate started after him, way back in chapter 1.
The other major event of this chapter is a step in Miku's "awakening", so to speak. Up to this point in the story, she has only her programming to go on, and despite this being Midchilda, her programming is that of a Vocaloid. The Sergeant is the one that has to inform her that she is, at some level, a weapon as well.
She doesn't take that well. When I said in the last chapter notes that I draw inspiration from the Project Diva music, that means songs such as Your Diva (Anata no Utahime), melody, Electric Angel, and The secret garden. These are love songs to some extent, and also songs devoted to the making of music (well, the first two at any rate), and so this Miku at this point in time doesn't want to be a weapon, really.
Rest assured that that won't last forever. After all, there's always Love is War (Koi wa Sensou) and Disruptive Diva (Houkai Utahime -disruptive diva-) on the list of Project Diva songs...