This escalation was not caused by the demonstrators' behavior, in which there had been no change, but to new instructions given to the military forces on the ground. Whether by explicit instructions or by a tacit nod and a new "spirit of the commander", the finger on the trigger was loosed and authorization given for the tear gas containers as lethal missiles.
See a slide-show of photos of the killing here.
Below a video from Brazilian newscast on the killing. The claims of 'violent riots' by the Israeli authorities fall quite flat. Abu Rahma was clearly unarmed and not engaged in any violent act.