You are in a straight 400 m race. You overtake the last person.
What position are you in now?
If the last competitor (L) is in front of the given competitor (C, say); it follows that L can NEVER be the last person.
It is however possible that C can overtake L and yet L can be the last competitor/person. For example C is NOT an competitor but C is following L's progress outside the running track.