Sam watches his face in expectation, assuming those widened eyes are the precursor to a step back, then another. A bid for reconsideration: maybe that key isn't so unattainable after all. Her face doesn't hide her surprise when he offers his forearm instead.

Her knowledge of anatomy is limited but he seems sure. She will have to take his word for it. It doesn't hurt that he volunteers to go first.

She doesn't prolong the anticipation: without further ado, she touches the blade to his skin, slicing carefully along the line he indicated. Sam's hand is steady and it takes minimal pressure to draw his blood. She wants to want to look away when the crimson trickle starts to travel down his forearm. She doesn't.