 With the devices armed and each boot laden with its lethal cargo, Hanna then gave the final instructions to the drivers of the three car bombs and they set off on their mission towards Dublin's crowded city centre.Two of the vehicles were escorted by "scout" cars for the bombers' escape back to Northern Ireland.Hanna and Jackson meanwhile left Dublin before 4.00 p.m. to return to the north, with the bombs at that point unexploded.