Heh, yeah, there's other explanations, I agree.
But just nitpicking yours (if you don't mind). If the spell took 9 turns to charge, he wouldn't have been able to cast anything else in the meantime. So, the spell that bends the rules to keep Sylvia alive would have to last at least those nine days. Though this is possibly explained if he split his turn's juice between casting the two at the same time.
But anyway, I also thought that Sylvia played a very... interesting... part in Charlie's plan to kill Parson by closing the portal in the city being an inferno. See, Charlie told the (dittoed) King Slately about the plan to cut off the MK portal behind Parson before any of the fires were started (when Sylvia was still allowing the guys to look for the 'hidden' unit in the garrison) Maybe I'm reading too much into it, but it just struck me as odd, as if perhaps Charlie had known that Sylvia would play some important role one day, and would thus make some deal to save her (essentially getting paid to help himself)
Edit: The above would also explain why a seemingly level 1 stabber was important enough to have a deal of that kind made for her.
My two cents
What Parson's slogan should have been: "We break things. Sometimes that even works."