I don't think she even could, but anyway she's not even anti-human. It's just that she now also values demon and monster life instead of just human life.
Yeah, I guess having a dungeon incident just before your rank promotion and then another after you're promoted isn't a good look. Hell, 'member when we were falling for Mikage's dungeon-inspector (or something like that, can't 'member) guise because of how believable it was?
That's actually a fairly reasonable point. I guess it's another reason to work with teammates who share the same goals.
I really doubt Challe's party had this in mind when trying to recruit Tina, they really don't seem that savvy despite being B-ranks. Either they had no idea about this (and just relied on Tina to solve this for them since she already had the info from Garon unbeknownst to them), or maybe the dungeon's layout being essentially a puzzle isn't deemed that big of a problem by the adventurer's guild for some reason (like say, allowing only 1 team at a time).
Though I don't know why Garon didn't just plan for Tina to use this dungeon's characteristic for stalling Challe's party. "Oh whoops I pressed the wrong button and now we're back to square one, teehee sorry guys this is my first time in this dungeon so I don't know how to navigate in it yet I swear."