Free will does not mean unpredictable. It means determined by the will of an agent. If you watch somebody take an action that does not mean they had no choice I the matter. Even if you watched them through a magic crystal ball that let you see their action before they took it.
There is a difference between a disinterested observer as in your example, and the Being that created the whole system that results in people certainly going to Hell, especially when most traditional Christian sects believe that the number of people going to Hell will far outnumber those going to Heaven.