Sam’s back hits something, and it hits it hard. His ears are ringing and he feels like his spine has just broken in half, but he can still feel his legs if the pain is any indicator of it, and when he starts sliding down, he can dig his heels into the ground as he grabs a hold of the metal frame behind him. It’s the Impala. Thank God, it’s the Impala. His hand’s bloody and he can’t see much when he turns around and searches for the door’s handle, but he finds it just in time to slip inside the car and slam the door closed as the monster charges for him. It crashes into the car and Sam’s still gasping for air as the impact rocks him sideways, making it difficult to get the car key into the lock.
He manages, however. The car speeds backwards, turns, and he steers it for the road as quickly as he can - he’s bleeding, but he’s not sure how badly yet. He needs Dean for this. He needs Dean and proper weapons.
This was supposed to be a scouting mission, not a kill mission.