I know we aren't supposed to be speculating here, but seeing as the thread exists, but assuming a hypothetical, similar case on a desert island with one controlled runway, where an aircraft is taking off and another is on approach for the same runway... assuming the aircraft taking off actually was cleared to take off, one might think ATC must have thought the separation sufficient to give the landing aircraft clearance to complete its approach and land.
If it was that close isn't the aircraft behind supposed to initiate the evasive action, i.e. GA? And would not someone in the tower be asking why the controller permitted the approach to continue without recommending a particular course of action to one or both pilots?
On the other hand, if an aircraft was to enter the active runway without clearance to take off, and with another aircraft on short final, one supposes the pilot attampting to take-off might feel a little embarrassed.
Or is one missing something?