Suppose that we want to have something happen when the player leaves a region we've defined. "Instead of going from (the region)…" will not suffice for this, because this rule will be invoked every time the player successfully leaves a room within the region, whether or not he is going to a room that is also in the same region.
Instead we need a rule that is a bit more specific, like this:
Test me with "s / w / e".
It's a bad time to leave Neptune.