Hmm... The annotation appears to assume the only choice was between staying in the cavern indefinitely or trusting in Yomen's good grace. However, my point is that's a bit of a false dichotomy. There were still options available to Vin: options that were not outside of her character (as the one she chose, I believe, clearly was). I think that willingly allowing herself to be put into stasis where she couldn't assess, contemplate, and react to her circumstances, where she would be completely vulnerable to the whims of her captors, would be so abhorrent to her that she would only do so if her life or a close associates were immediately threatened.
now THAT's where the problem is, as Sazed would say, I think.
the reason that annotation starts with a comment about Vin being impulsive is because her split-second assessment of her pewter and duralumin stores (and what she could do with them) lead her to think she'd be able to shake off the poison. As I remember, she was legitimately surprised when the poison persisted after she'd run out. Surprised and disappointed. There's no resignation in her action, merely a gamble gone wrong. Yes, there were other actions she could have taken, but the one she decided to take was completely in her character.
I'll point you back to the first book, where Kelsier sneaks into Kredik Shaw, and Vin follows him - the annotations reference both of their impulsive natures...hold on while I get it.
HERE it is -
"Following Kelsier this night is probably one of the dumbest things Vin does in this book. Letting her follow is undoubtedly the dumbest thing Kelsier does in the book. Yet, these two characters are alike in more ways than they may seem at first.
Both have a sense of brashness that borders on the foolhardy."
And if you'll remember, that too was a gamble that didn't go well for them - Vin almost died there.
So I think there's been enough evidence that Vin's been intended to be a very very impulsive character. Downing the wine and thinking she'd be able to fight off the drugs
and her enemies was foolhardy, and possibly not her best shot, but its what came to her first. And if there's anything we can count on Vin doing, its going with her gut.