This is not a question as much as an answer (from FFG).
Quote
"Overrun triggers when you enter the space, but the restriction prevents you from entering the space, and the damage can’t be triggered. Overrun doesn’t quite clear this restriction."
I guess the question could be something like: The movement section in the RRG tells us that a figure cannot spend its last movement point to move on top of (through) another figure - is this also the case if you have played Overrun and that doing so would kill that figure?