Runner has access to the entire bag, he ran straight thru the bag and was in the right. Wes Rea interfered with him and caused the collision. Ashame since the ball rolled way into foul territory, the runner couldnt advance to 2nd because of being on the ground semi injured.
He does have access to the bag, but my point is he never attempted to stay in the running lane and by doing so, interfered with the throw by the catcher.
The throw carried the the first baseman's arm into the runners path, I agree, but its my understanding if he's running on the fair side of the base line and interference occurs, the runners out. That's why the running lane is clearly marker by a chalk line starting half way down the 1st base line.