They are having these hallucinations.
"Beautiful visitors, strange landscapes, all of it so vivid."
"You think it's the machine?"
"I think it's something the machine has opened up in my mind. And I'm not the only one. I've heard reports of others having
similar experiences. And then there's the drowning."
"Yes. One of the visitors drowned in their bathtub a few days ago. They found them with a look of terror on their face, like s/he'd seen something that had scared him to death."
"And you think it's connected to the machine?"
"I do. I think s/he somehow stumbled upon the same thing we did. And I think it drove them mad. But I can't stop now."
Sharlyn 1+2 realize that they had stumbled upon something much bigger than they had initially anticipated. However, it is also incredibly dangerous, as any miscalculation could result in being pulled into the black hole's event horizon, never to return.
They step into the machine, Shaklyn 1 watches in horror. S/He wants to stop Shaklyn 2, to tell them it's not worth the risk.
But s/he knows s/he won't listen. And so s/he can only watch as the machine hums to life, and Shaklyn 1 disappears.
The machine's lights flicker and fade.