How to find if an actor is in front or behind another actor?

I’m creating a door and needed to establish if the player was behind or in front of it… and Garcia’s solution works perfectly. Whereas I hasn’t been able to correctly implement the other solution. Although I believe it also should work. So it’s +1 for me too. I may have interpret something wrong with the vectors (because the gun example is a little different but remains the fact that this is simpler… and… it works.)