Thanks for the TL, as always (I love this manga, it feels really grounded and unique).
I'm wondering how the author will explain Mochiko's personality change. The last time one of her associates was struggling, she started a part-time career as a pimp. Now, she's being nice to the MC and getting her back on track? Maybe she appreciates Kurumi's work and will trap her in underpaid analyst hell forever but I hope she does something nasty (and consistent) in the next few chapters
Mochiko wasn't really friends with the other one, the one she sold off pissed her off by being carefree, a thoughtless trend follower, and likely Mochiko was jealous that the girl she sold off came from a family with two parents and no "real" hardships.
To Mochiko, the one she sold off was just a spoiled brat that didn't know when to cut her losses (bitch put her college money in the market - the college money HER PARENTS gave her - Mochiko had to sell herself to get school money), and too stupid to go back to mommy and daddy before it was too late.
Mochiko, despite her tough act, actually likes Kurumi and sees her as a friend.
Mochiko gained respect for Kurumi's trading ability too and even though Mochiko was too busy being a bitter+stubborn bitch to strongly voice her concerns and tell Kurumi to exit the Swiss trade - She REALLY wanted Kurumi to get the hint.
Kurumi probably wouldn't have listened anyway, honestly.
Also Kurumi has suffered in her life (losing her mother), so Mochiko can't use her normal method of convincing herself that she shouldn't do anything which is thinking: "This person has never suffered, they should learn what reality is like".
Kurumi managed break into Mochiko's lonely bitter heart and there was about zero chance that Mochiko would let her die and Mochiko probably thinks Kurumi has suffered enough at this point.
Also, although short-sighted and misguided - Kurumi's reaction was to "take responsibility" rather than beg for help/money.
The Above was likely much more respectable in Mochiko's eyes when compared to the girl she sold to a whorehouse, although Kurumi's childishly tendency to hide her mistakes from other people even when she shouldn't is something that Mochiko has just learned about and is about to address, I guess.