I haven't had a chance to read this all the way through, but it looks like the most comprehensive reports into the flotilla attack yet. Here is one particularly chilling passage on the initial Israeli attack (p.22):
Around 4:10, messages from the ship Defne, which was part of the flotilla, began to be received by the Mavi Marmara, which stated "Mavi Marmara, all the boats and ships are approaching you." Shortly after this warning was received, when most of the participants were performing their morning prayer, at around 4:30, pursuit boats carrying masked, armed soldiers came alongside the boat. There were at least 10 Israeli soldiers in every boat. While the soldiers in the boat were trying to grab onto the boat with heavy grappling irons, they also started to fire on the ship. Three different shots were heard. The highest frequency sound was the most intermittent. The second most frequent heard sound was a full and loud noise that resembled a gas bomb. The third sound was the constant sound of machine-gun fire. While these developments were taking place, military helicopters full of armed soldiers came over the ship and soldiers started to repel down. The soldiers were shooting as they were descending.
Here the most important matter that needs to be emphazised is that the operation developed in a hostile manner that was geared directly towards killing. The Israeli soldiers did not open fire on the ship as a warning, but rather to directly kill the unarmed civilians on the ship. At this juncture, the Israeli soldiers shot a couple of the participants on board the ship, where there were no arms of any kind, in the head, killing them; they also injured a number of people.