Bella's life isn't just less valuable than Harry's. Her life has a large negative value. Harry should be trying to prevent her escape.
If she kills again, then yes, she shouldn't be saved. But this is a claim about consequences unrelated to the value of her life itself. If she can be saved and prevented from killing others, she should be.
By TDT, the fact that she did a lot of evil things in the past is reason enough to assign her life less value.
- This thread has run its course. You will find newer threads in the discussion section.
Another discussion thread - the fourth - has reached the (arbitrary?) 500 comments threshold, so it's time for a new thread for Eliezer Yudkowsky's widely-praised Harry Potter fanfic.
Most of the paratext and fan-made resources are listed on Mr. LessWrong's author page. There is also AdeleneDawner's collection of most of the previously-published Author's Notes.
Older threads: one, two, three, four. By tag.
Newer threads are in the Discussion section, starting from Part 6.
Spoiler policy as suggested by Unnamed and approved by Eliezer, me, and at least three other upmodders:
It would also be quite sensible and welcome to continue the practice of declaring at the top of your post which chapters you are about to discuss, especially for newly-published ones, so that people who haven't yet seen them can stop reading in time.