Ruby had expected the hysterics, she met Sam's gaze for a moment and without a seconds hesitation transfered the flashlight to her other hand and adjusted her stance slightly ready to stop Jessica if she tried to run. There was really only an easy way and a hard way to do this but in either outcome the womans hand got cut.
"Its still Sam Winchester. But that thing that attacked you, the Yellow Eyed Man, he's not the only darkness in the world and Sam needs to make sure that you are who you say you are. You just have to let him cut your hand. Thats it. Thats all it will take. Then we can explain"