Basically, be as negative as you can while talking to Jenna while walking in Tetanus Alley.I.e. Agree with her that people can't be helped who don't want to be, and respond "this town breaks people" to the following choice.
Thanks. I did manage to get to her bad ending somehow eventually, but to my knowledge I didn't do anything different from my other try before that, though I probably just did do it wrong.
