Theory:SJA television discontinuity and plot holes/The Mark of the Berserker

Either it hasn't flashed in the right situation before;
 * Where has the red flashing light on Mr Smith's screen cover come from? It's never been there before.

Or it was 'installed' after mr smith rebooted;

Or Both!


 * Wouldn't it be better to destroy the pendant or lock it somewhere safe instead of throw it into shallow water where it could easily be found again?