Fun fact...

I love reading Valucre character sheets. 

Hahaha, it would have come down to, was his defense actually legal? Could he, in fact, have actually caused the explosion? If so, then to me, that would be legal. You'd have to deal with what happened between your vacuum, his explosion, and then continue with your fire(or axe it, in favor of not having an explosion to the face). xD

Personally, I tend to work at levels that don't involve vacuums, or anything like that. xD