[She looks from Yuuki to Zero and back again. She's clearly missing something, but maybe separately they can tell her what's up with the huge polka dot elephant in the room. (Her money's on Yuuki.)]
Sure, you can prick my hand. It's okay, I heal up really fast. [she hold her hand out with confidence, trying to smile despite the tension.] You don't have to worry.
[sneaking a glance at Zero,] And you said I can't hurt her, right?