She knocks, to be polite.
"Now I'm trying to figure out what would've happened if I'd had to come to some kind of agreement with - her."
"Thought experiment type circumstances," says Juliet dryly. "I haven't troubled to think of any."
"Happily yes. I wonder how much of my reluctance to get rid of my soul is the irrational fear that it will turn out differently the second time."
"...That's not completely irrational. It does depend on why it worked so nicely the first time, and I think we've only got speculation, there."
"Not to put too fine a point on it." She sighs. "I can think of, like, hack movie plots, but not actual reasonable plans."
"Yeah, like, in a hack movie plot, we'd make sure you couldn't do anything too awful if de-souling you went badly. Emergency mint containment protocol, leaving the soul stuck to your torching, making sure me or Tony could torch you at any time if we didn't like how you turned out. And then probably there would be a tragic misunderstanding and we'd all three argue vehemently before you, I don't know, kissed at least one of us to appropriately swelling music and we knew we were fools to have ever doubted you. Hack movie plot."
"Whereas," he sighs, "what actually happens is that either I convince you both I came out just fine and then am perfectly well-behaved, or convince you both I came out just fine and then kill everyone. I'd bet quite a lot on the first outcome, mind you."
"Well, the first outcome would be fine if it weren't for you being all attached to your soul. The second could maybe be forestalled if we got around to implementing mindreading."
"I'm not sure I should be as attached to my soul as I in fact am." He sighs. "I'm not sure of much right now."
"Mindreading wouldn't help, anyway. If I could keep anything back, I could fool you with it."
"The amount of mental privacy I would need from such an arrangement is more than sufficient to conceal an underlying desire to destroy the world. I am in a better position to know that than you are."
"I believe that you could keep me from being sure that you weren't fine. I'm not sure you could convince me that you were definitely fine."
Half a beat.
"But it's me," he adds.
"Now that we've had this conversation it may become completely impossible to convince you that I am definitely fine," he snorts, "but if it doesn't, my point stands."
"You don't think there's any space between it being completely impossible to convince me that you're definitely fine, and it being absolutely guaranteed that you can convince me that you are?"
"I don't think there's any space between being able to convince you that I'm fine when I'm not and being able to convince you that I'm fine when I am."
"I guess that makes some more sense." She sighs, she squeezes his hand. "I want you to be fine. I really, really want it, and I guess if you can live with being like this then I don't need to lose metaphorical sleep over it but I'm going to keep thinking." She lets out a soft, sad chuckle. "Maybe one day we'll run into another one of you who eventually figured it out."