What mentality is testified to by the gun-boat shelling the bush? What have we already heard of that this calls to mind? What do we eventually meet with that in turn calls this to mind?

THe mentality is a total disregard for human life. They indiscriminate shell the bush not mindful of any life. I suppose the Grove of Death reminds me of this. I'm not sure about what you are particularly referring to with your last question.

The Gun ship is also a display of power, authority and superiority of the European invaders.