This is all speculation, when it comes to motive, how and why the victim was chosen and so on. Maybe the truth will come out. At least the attackers survived, so regardless of how some people may feel about that, they can at least be questioned.
What is pretty obvious to me though is that the attackers were pretty poorly organised with regard to their weapons - one handgun between them, and a rusty old revolver at that, according to reports. One shot was fired, the gun blew back and injured the shooter, which indicates that either they were using undersized ammo (wrong ammo) or that the barrel wasn't clear.
And yet, this is being treated as a terrorist incident...
You'd think that if there was any kind of terrorist organisation behind it they would at least have a functioning gun each, and maybe some grenades, so that they could at least have a realistic crack at the police before their glorious martyrdom...
We keep hearing about home grown terrorists being trained to commit their acts of terror, but these two seem to me (based on just the above) to have been acting alone, with no support, no training and no equipment. Strange, but in a way, reassuring.