The investigation will need to carefully examine the behavior of the crew and their leadership and guidance to the passengers.
Looking at footage/pics of other evaluations, it appears that many passengers ignore the commands of the crew to leave everything and get out. There is nothing a crew member can do if a passenger gets to the door with a bag as attempting to take it off them would only slow the evacuation further and the crew at the doors have nowhere to put the bags.
What needs to be investigated is not the behaviour and leadership of the crew, given that it seems all but 2 people survived and exited, but rather the behaviour of the passengers who seem to value their possessions, thereby placing others at risk.