Unfortunately, Sam did know what Dean meant. Maybe better than Dean did. His brother had always seen things as black and white-right and wrong. Except when it came to Sam. It was an uncomfortable responsibility, knowing that no matter what he did or how far gone he was, Dean would find a way to protect him. He didn't like it and there were times when he thought that his brother should have ended him and been done with it-particularly when he'd been running around without a soul. But it was what it was.
The look on his face probably showed some of the guilt over what he'd done to Fred, but he didn't say anything. Instead he shifted his attention to the apartment building.
"It could still be a joke," he said, though even he didn't believe that. "Then again, when is it ever a joke or a hoax with us?"
There was a faint attempt at a smile as Sam stepped out of the car and moved towards the building. If he was being honest, he felt just as violent over the idea of anyone trying to hurt Fred again too. Maybe it was because he felt responsible for her after what he'd done and maybe it was just because she'd shown him a great deal more kindness than anyone else in her situation might have done. It didn't matter. What mattered was getting up there and figuring out what was going on with the frog sightings.