[Alright, this has already started to do her work for her. They're frazzled, bits fraying off at the edge.

Now all she needs to do is pull the string.]

That's f-fine, I just... well, if you're going to run into my double, I wanted you to know about the determination experiments.

[She lets those words weigh heavy for a minute before continuing; but this time, she's standing up a little straighter. Loses a bit of her fearful demeanor.]

See, Asgore gave m-me the human SOULs to try and, uhm, b-break the barrier, so I decided to try and give monster SOULs the same staying power as humans. That way, we wouldn't need human SOULs. So I built a machine to take their Determination. And then I injected it into m-monsters.

[She is, specifically, looking as unremorseful as she can here; even, almost, mad-sciency with how excited she seems to be getting.]

But as it turns out, Determination needs a stronger SOUL to h-handle! So... they lost their physical bodies. They melted together, into amalgamates. Nothing better than animals.

[She's advancing on them now. Frisk may not know Alphys well, but they should probably have gotten the hint they may have found her double before they found her.]

I lied, to e-everyone. And locked them in the basement of my lab. And left them. T-To die. But it's not so bad here, now that they're gone.

[She's standing over them now, the light on her glasses obscuring her eyes behind them.]

At least I know where to get more determination, d-don't I?