Sam saw the movement as well. Something was hugging the shadows and making it's way to the shops. He had his hand on the door handled when the witch slipped up to the door and there was a brief flash of light as she waved her hand over it and then the door fell open.
He didn't wait any longer to observe what might happen from here. If he was right, this was the last ingredient for a spell that could do an awful lot of damage.
Gun in hand, Sam got out of the car and moved forward. He pointed it and called out, not ready to just shoot without an airtight reason to do so.