Physical Combat Between Characters

So in one of my recent session two of my players had a duel. I wasn't sure exactly how to use Seize by Force to have them do this duel because Seize by Force imply you are both dealing and taking harm from an npc but Act Under Fire is something that allows you to dodge. The rules we came up with on the spot was using Seize by Force as an "attack" and us Act Under Fire as a "dodge" move so the question I have is has anyone come across this before and how did you deal with or does anyone know a good way of dealing with it?

I always have both players roll to seize by force, both make their choices independently, and then have a single exchange of harm that includes all of their choices.

The choice to suffer -1 harm is all the dodge I give them!

-Vincent

Thank you grand masta Vincent for being ever present and helpful.

Sure thing!