Discarding the Deathmask and spirit of the rules

So I was playing with my wife, and was forced to help her defeat a level 18 Pluto via a passion potion. I discarded my Death Mask to make Pluto disappear, as he is undead. My wife claims that this is not helping her to defeat the monster and that our combined power levels would have been enough to defeat Pluto, and violates the stipulations put forward by the Passion Potion. Any help as to correct interpretation of the rules would be appreciated.

Discarding the Deathmask and spirit of the rules