Why was it overland by the Columbia/Venezuela border on a flight from Panama to Martinique?
Where he ended up wasn't too far off a straight path from Panama to Martinique, but presumably he was there due to his announced intent to divert to Maiquetia (Caracas) when he first reported engine problems.
Could not all have survived if he landed on the sea, especially if he had altitude to position it by a beach?
The recent thread on the ATR in the sea off Italy contained a great deal of discussion on this issue. Chances of a casualty-free ditching are almost nil even under the most favourable of circumstances.