As I read it, it seems that the intent is that there is a chance that the victim could be hit by ballistic attacks that pass wihin one inch of the victim. Therefore, if the shot misses by four or more (modified by the SZ of the target), then the victim is hit and the target is not. The victim is flailing about and is not bing careful about their surroundings or the lines of fire of friends or enemies.
If sing, sang, and sung, sink, sank, and sunk, and drink, drank, and drunk, how is it that it isn't bring, brang, and brung, think, thank and thunk, and ding, dang, and dung?
Don't even get me started about bad, badder and baddest. Run, ran AND run...again? C'mon!