She just didn't expect the dark forests of Mirkwood.
The air is foul and heavy here. It poisons her mind, as well as those in the company. They snarl at each other and therefore don't notice the spiders until it's already too late. Fortunately, Bilbo is able to cut them free, but they lose Thorin in the madness and then the elves are suddenly upon them.
"Let go of me!" Kili shouts, her voice rising with panic. The elf searching her must think that Kili is like her brother, hiding multiple daggers under her coat. There's a harsh tug on the collar of her tunic and the elf freezes, staring down in surprise at the bindings across her chest. Kili jerks away and steps closer to Fili, trying to ignore the way the elf watches her. Fili glances back at her but she shakes her head. It's best if he not know what just happened. Still, Fili knows her better than anyone, and gives her hand a reassuring squeeze, which she returns.
The leader of their captors, the elf with blond hair and black armor, barks out an order to others before their company is dragged away.