>>646I re-read it this weekend and you're right. Red knew what he was doing and he knew what would happen to Arthur.
I'm still not sure what to make of the ending but I did notice something- The first time he describes the golden ball it's quite plain. Copper coloured, not gold and mentions that it looked like it would not be capable of glowing or dancing as per stalker folklore. Then as he gets closer, he refers to it as the "dancing, winking ball."
I suppose you could infer from that that this is a sign that the ball is activating or has activated and then that his innermost wish was already granted before he told the ball what he wanted.
I've never been much chop at reading into stuff so I'll need to think about it some more.