Re: Medical(ish) question
In ancient and mediaeval Europe, cauterising a wound after amputation was the norm.
Death through blood loss, shock, and infection were all still massive risks.
I'm not sure a sword in a fire would be hot enough, though - cauterising irons were used which were better shaped, and left in the ashes to get red hot.
A normal fire will make a sword hot but I'm not sure it would get hot enough to cauterise unless left for a good few minutes in the hottest part of a good fire.
Also, the process could damage the sword as well if attempted.