Sam vaguely remembered hunting vampires with his brother and Dad a while ago, back before he had gone into college and had spent his time traveling the country with his brother and father in tow. He knew that the bites were deadly, especially if they clamped on for long enough and managed to bleed a person to a certain extent. She had to be pretty strong willed to have recovered from something like that overnight, at least. But Sam wasn't exactly willing to take a leap of faith on Faith (hah); the monster inside of him was stronger than a vampire and he wouldn't hesitate to kill her with a mere snap of his fingers.
"What if he gets out again?" He asked uncertainly. "What if he hurts everyone? I won't be able to help. I'll be gone."