@Kayriel
Nicely put.
Judging by their comments, it's a little bit over the top for them to comprehend, but at least you try.
I would also add that at this point she is at least somewhat emotionally invested in the guy, so her thinking is not 100% cold steel logic. I mean, when you mother tells you to wear warm clothes, it's not like she thinks you're going to die otherwise. She's just so worried about you that taking chances for her isn't an option.
This girl is a worrisome type from the beginning, being a supporter to boot. Characters like this create a healthy duo with reckless types. Also one should bear in mind that his death would most likely mean her own death too, so by worrying about him she also worries about her well-being. The author isn't really clear about this, but so far it looks like in order to leave a dungeon one needs to clear it. Heck, I would be even more cautious and strict in her shoes.