"It is pleasant when you do it but it may simply be that it is a thing you are doing.  It is a meat-noise, and when you are not near me I do not like those."

"There's instrumental music too.  ...Music that humans make using - special tools, that make sounds we think are pretty.  ...Hey Dr. Salt, you couldn't play something over the intercom, could you?"

"Not on short notice, it's not really set up for that.  Sorry."

"On long notice?"

"Within a day or two?  Sure, if Hijazi gave the go-ahead."

"Mm."  To 682: "Are there any sounds you do like?"

Rumble.  "I like the sounds metal makes when you rip it apart and scrape it and bang on it."

"It's not something humans usually listen to for fun, but I think it'd be pretty easy to find a library of tearing and creaking metal sound effects for you."

"The alarms are also nice."

"We use the alarms to warn people when there's an emergency, so it's really important that they never go off when there isn't an emergency," Charlotte says apologetically.

"You could switch to new alarms."

"It would be a lot of work.  People would have to design new alarms, and then everyone in the facility would have to be trained to recognize the new alarms instead of the old ones, and there's a risk it would confuse people which would compromise security.  I had to promise Dr. Hijazi we wouldn't compromise security on you, since she hasn't talked to me enough, and I haven't talked to you enough, for her to trust me about trusting you."

"Mmm."  Disappointed.  "The tearing metal noises would also be good if you can make her agree."

...She will save disentangling that phrasing for a future conversation.  "All right.  So we have turning off the lights at night, and tearing-metal ambience for you... I wonder if it would help you to be able to actually tell time.  Do you know anything about how humans keep track of time?"

"No."

"We divide days up into twenty-four hours, and we number the hours - in a kind of weird way.  The start of a new day is the middle of the night, about halfway between sunset and sunrise, and that hour is numbered twelve.  The first hour after that is numbered one, then two, then three, gradually up to twelve again, and the second twelve is the middle of the day.  Then the first hour after the middle of the day is another one, then another two, and so on again.  The hours from midnight to eleven in the morning are called A.M. and the other hours are called P.M.  I don't know why we do it that way."

"That is confusing.  ...But it might also be good to know how many hours are left in the day, as well as know how many days it has been, or whether it is day or night."

"I can talk to Dr. Hijazi about that too."

They don't come up with any more particularly stellar ideas, for what could make a perpetual acid bath less unpleasant, before Charlotte's time is up.  Dr. Salt lets them know.

"I have never returned to the acid bath willingly, before," it says.

"What's it usually like?"

"Sometimes they deploy weapons that render me unconscious, or damage me enough they can move me by force.  Sometimes they herd me in with lesser weapons or confuse me."

"I'm sorry."

"It is easier not to be angry and scared when you are near me."

"Will they let you stay until the tank fills."

"I think so."