A shake of their head. She could really learn to listen, couldn't she? Except it's not so surprising, to not be listened to. To have assumptions made as they're spoken over.

Maybe she's another of Sans' friends.

"No. You're not there when I kill them." A statement, not the slightest bit of hesitation in their delivery. Not much of anything in their delivery; but they know. She won't be there.

As for her question...

...

"Maybe not. Doesn't matter." They look down at their blade, shifting it between their fingers. Watching the light play of it's already grimy surface. "They want to die anyway."