Might be useful to recall the second half of “I fought the law and the law won.”

↓ Transcript
Panel 1:
Nancy, suitably scolded, scratches her head.

NANCY: So, reading between the lines, you want to take on the Yeomanry?

SI: Too bloody right I wanna take on the Yeomanry.

SI: An’ I think I know how.

NANCY: Oh?

Panel 2:
Si packs her violin, in preparation.

SI: I knews they’z woz quantum cuz I felt them paper-cuts before.

SI: In the tube, when we woz lost ‘tween dimensions or whatevs, we went through that storm, ‘member? Wif the lightning bolt monsters?

NANCY (off-panel): You think the Yeomanry and those monsters are made of the same stuff?

Panel 3:
Flashback to when Si halted the Storm in the tube with her lightning powers.

SI (box): ‘Yeah! An’ I was able to stop ‘em wif my violin! Get me down ta Whitehall, I might be able to do it again!’

NANCY (box): ‘You warded off a couple Stormlings back then, we’re talking about an army of the things down in Westminster. You sure you’re up to it?’

Panel 4:
Si hops off the desk. Taking the battle to the enemy seems to have energised her.

SI: Only one way to find out!

NANCY: Wait. Before we go do crime, I want you to think through the implications of what you’re proposing.

NANCY: If the Storm and the Yeomanry are made of the same stuff, that means Derrider extracted them from the same place and has found a way of controlling them.

Panel 5:
Si zips up her jacket, not sure what Nancy is getting at.

SI: Uh…yeah? I guess?

NANCY: You’re not at all curious how she is able to do that?

SI: I mean the losers we’ve run into have all been able to pull off some weird stuff, we’ve managed.

NANCY: That’s not what I…

Panel 6:
Nancy beckons Si to the spiral staircase.

NANCY: …y’know what? Never mind.

NANCY: Let’s go do crime.

LEWIS (box): ‘Pandora-2, Gold Unit in position.’

DES (box): ‘Pandora-3, Amber Unit in position.’

SAM (box): ‘Pandora-1. Stand by.’