COPIED FROM THE POSTED RULES:
Ranged weapons cannot be used against zombies in your square when there are other players in the same square (hand to hand combat only). If you are the only player in the square with a zombie you may use a ranged weapon. Shooting INTO a space where other players are will result in the players being hit before zombies are hit. With multiple targets in a space, the order of taking damage from a successful hit with a ranged weapon will be as follows: player, walker, runner, hulk.

My take on that would be that if P6 was OUTSIDE my space he would have hit me, but since he is within my space, he made an illegal action and did not hit me. I will play as if I'm alive until ruled otherwise.