Council of Florence explicit states that shedding your blood for Christ DOES NOT save you unless you are already untied to the Church.
This argument is a really stupid understanding of the Council of Florence.
People who die for the one true Faith ARE united to the Church.
The Council there is excluding from salvation HERETICS who die for Christ. Such people can only have a human faith and love for Christ, and cannot be rewarded with salvation therefore. They can legitimately love Our Lord in a natural way, but on account of their heresy they are cut off from the Church, and are incapable of supernatural charity. This explains why we can see heretics are able to be kind to their neighbour. It is a natural charity, not a supernatural one.
One who has the true Faith and gives up their lives for it (which is the most dear thing a human being has) possesses a supernatural Faith and therefore a supernatural charity, which can only be rewarded with eternal life.