Forgive me for chiming in where I have less than the requisite amount of expertise and/or knowledge of the game.
It is my opinion that you are reading, "by the shortest route," too literally. If the model is allowed to ignore priority, then the shortest route to the targeted model is redifened so as to allow the leaping model to engage the target without being in base contact with both models. Therefore, your diagram is not, technically, correct. The shortest route to the target would avoid model "B" altogether, and the line should be redrawn so that "A" is only in contact with "C".
Does that clarify it?