@grandygon if they have record or knowledge about hell flames, they should knew how to seal it better....
they knew the flames also burn the souls probably when they try to seal it...
MC's suffering and lose conciousness thinking he gonna 'disappear' happen right after his soul started burning, so i think its not that long...
the flames probably just like 'living being', the flames satisfied after 'consume' the victims, then it calm itself until the flames got 'hungry' and demand another sacrifice...
and rather seeing MC got tortured and die slowly death, better die immedately....
i assume that Village is place of Big Shot since they protecting the world from Hell Flames, that even still recorded after 1k year has passed...
so if MC 'successfully' run away, i doubt the world gonna leave him alone when the village got huge influence on that world...
moreover MC cannot use 'fire thingy' and just using his fist and kick....
so for me what Master did is still acceptable if we use 'Medieval' logic...