Usually Bell doesn't even reveal the recorder's existence in front of anyone. Having crossed that hurdle, she doesn't mind that she has to speak aloud in front of Sherlock to find what she's looking for.
Sherlock just sits.
After a few hours, Tony knocks on the intervening door.
After a silence, Bell says, "It's your room."
He doesn't retreat immediately, but hesitates, watching Sherlock.
"Hi," Bell says. "Um, how are you?"
He shrugs. "Better. You?"
"I'm all right. Been listening to old conversations. At least four people I've talked to in Milliways think that the economics of Panem make no sense. I'm trying to think of a way to swat the economy so it falls over like everyone seems to think it ought. It seems like the Districts would do better in that case than the Capitol would as long as everything fell over hard enough that the Capitol couldn't feed an army. Especially the ones that are food exporters, but I think even Twelve and Eight and so on produce a lot of their own food, just not enough to send to the Capitol."
"...Why's everybody think it'll fall over if you smack it?"
"Wait," says a man's voice, "where are the financial systems in the Districts? Why can't people get loans? Your mother makes her income sewing and she can't afford a sewing machine, but she could be ten times as efficient if she had one, it would pay for itself, any sane lender would give her the money."
Bell pauses the recorder. "That's the sort of thing they say. So I guess the question isn't so much why it doesn't fall over as why it doesn't... puff up like a blowfish. Why there's so many inefficiencies around that could be exploited. Which is less interesting for a project of overthrow. But more interesting for a project of building everything up again afterwards."
"Good question," Tony says thoughtfully.
Sherlock smiles just a little.
"So I'll read more econ," shrugs Bell. "But I think there's probably some law on the books forbidding loans, or something, and that's all there is to it. Your family used to be rich, was there any lending going on? Any complaining about it not being allowed?"
"I was too young to really pay attention back then."
"I wonder if Bar has a copy of Panem lawbooks. Now that would be educational. I can't think why I didn't ask her before - probably I figured they'd be more like people's diaries than like publications, but it's still worth a try."
"Good plan," he says, grinning a little.
Bell grins back at him.
Sherlock smiles some more.
"What do you usually do during downtime on a train?" Bell asks, looking around her like the answer might be written on the wall.
Tony glances at Sherlock.
"Not very much," Sherlock says dryly.
"You don't even have, I don't know, a deck of cards?"
"We might. Shall I find one?"
"The only game I actually know that I learned in Panem and not Milliways is Herringbones," Bell admits. "I don't think it's played outside of Four."