okay, some different bugs with /duel:

a) if one player suicides ( rocket ram ) its not counted as a loss
b) once he respwans, he can leave, you can't. then its a loss, for you.
c) if he's killed by somone else, he doesn't lose, the duel isnt aborted, and you lose if you leave.
d) ...yet to be tested.. does it work like this for /explode too?

Verified. There are a bunch of bugs with the Duel stuff because someone changed some code and didn't make sure it didn't break other stuff.
I'm fixing it now.