There were two important events for Vin in this last scene. First, she decides to stay and try to save Sazed. As I note below, this is a character climax for her. She’s not only grown to trust, but grown—somewhat—to sacrifice. Most of Reen’s harm to her soul has been reversed by the care and love of a group of idealistic thieves.
The second thing Vin does of importance in this section is fight without her Allomancy. I think it’s a nice moment for her, and lets her show some true bravery. One problem with making heroes as powerful as mine is that it’s sometimes hard to find a challenge for them. Also, it’s hard to present them as the underdog. In this scene, Vin gets to fight as just a regular person, and show that she’s still better than most people, even without Allomancy.
If you are viewing this on github.io, you can see that this site is open source. Please do not try to improve this page. It is auto-generated by a python script. If you have suggestions for improvements, please start a discussion on the github repo or the Discord.