Most witch burnings that have happened in the past, had a DM witness to the event and the DM usually takes care of the fire damage and visual effects. It seems more appropriate for a DM to handle such VFX and damage imo for what is probably a 'perma' event, which also helps allay any ooc complaints about said event which are likely to result. Having a DM witness to the rp and the actions, and to perhaps assist with visuals/damage and so on, just seems more appropriate than a script change that could easily be used in ways unintended (much like the traps have been lately).