Something next to normal, that's the thing I'd like to try

By the time the black-eyed thing occurs (and even the Delothrian's arrow part) she's already into problem-solving mode. Delothrian's arrow and the battle of wills are just something she needs to do in order to accomplish what she agreed to do. It's part Willow getting absorbed in a problem, part not wanting to show any nervousness that she does feel.